diff --git a/R/add_header_left.R b/R/add_header_left.R
deleted file mode 100644
index 25012af..0000000
--- a/R/add_header_left.R
+++ /dev/null
@@ -1,246 +0,0 @@
-#' Add a heading column to the left side of the table
-#'
-#' @description This function uses the same syntax as add_header_above. It will
-#' add a heading column with grouped rows to the left side of the table. It can
-#' act as an alternative way to `group_rows` to show grouped information. As
-#' `add_header_above`, users can use this function to add multiple layers of
-#' heading columns one by one.
-#'
-#' @param kable_input Output of `knitr::kable()` with `format` specified
-#' @param header A (named) character vector with `rowspan` as values. For
-#' example, `c("xxx" = 1, "title" = 2)` can be used to create a new header column
-#' for a 3-row table with "xxx" spanning row 1 and "title" spanning row 2 & 3 (
-#' two rows). For convenience, when `rowspan` equals to 1, users can drop the
-#' ` = 1` part. As a result, `c("xxx", "title" = 2)` is the same as
-#' `c("xxx" = 1, "title" = 2)`.
-#' @param header_name Column name that that extra column
-#' @param width A character string for the width of the new column. Values
-#' could be "10cm", "3in" or "30em", etc..
-#' @param align Column alignment. you can choose from "c", "l" or "r"
-#' @param bold A T/F value to control whether the text should be bolded.
-#' @param italic A T/F value to control whether the text should to be emphasized.
-#' @param ... Extra options to be passed into HTML or LaTeX. Right now there is
-#' only one for LaTeX. Option full_midline is a TRUE/FALSE option to control
-#' if the mid line needs to be extended to the end of row.
-#'
-#' @examples x <- knitr::kable(head(mtcars), "html")
-#' add_header_left(x, c("A" = 2, "B" = 2, "C" = 2))
-add_header_left <- function(kable_input, header = NULL, header_name = "",
-                            align = "c", width = NULL, bold = F, italic = F,
-                            ...) {
-  if (is.null(header)) return(kable_input)
-  kable_format <- attr(kable_input, "format")
-  if (!kable_format %in% c("html", "latex")) {
-    stop("Please specify output format in your kable function. Currently ",
-         "generic markdown table using pandoc is not supported.")
-  }
-  if (kable_format == "html") {
-    return(add_header_left_html(kable_input, header, header_name, align,
-                                width, bold, italic))
-  }
-  if (kable_format == "latex") {
-    return(add_header_left_latex(kable_input, header, header_name, align,
-                                 width, bold, italic, ...))
-  }
-}
-
-# HTML
-add_header_left_html <- function(kable_input, header, header_name, align,
-                                 width, bold, italic) {
-  kable_attrs <- attributes(kable_input)
-  kable_xml <- read_xml(as.character(kable_input), options = "COMPACT")
-  kable_thead <- xml_tpart(kable_xml, "thead")
-  kable_tbody <- xml_tpart(kable_xml, "tbody")
-
-  align <- match.arg(align, c("c", "l", "r"))
-  align <- switch(align, "c" = "center", "l" = "left", "r" = "right")
-
-  column_style <- paste0(
-    ifelse(!is.null(width), paste0("width: ", width, "; "), ""),
-    ifelse(bold, "font-weight: bold; ", ""),
-    ifelse(italic, "font-style: italic; ", "")
-  )
-
-  new_header <- paste0(
-    '<th style="text-align:', align, '; vertical-align: bottom;', column_style,
-    '" rowspan="', length(xml_children(kable_thead)), '">', header_name, '</th>'
-  )
-  new_header <- read_xml(new_header, options = c("COMPACT"))
-  xml_add_child(xml_child(kable_thead, 1), new_header, .where = 0)
-
-  header <- standardize_header(header, length(xml_children(kable_tbody)))
-  for (i in 1:nrow(header)) {
-    new_row_item <- paste0(
-      '<td style="text-align:', align, '; vertical-align: middle;',
-      column_style, '" rowspan="',
-      header$rowspan[i], '">', header$header[i], '</td>')
-    new_row_item <- read_xml(new_row_item, options = "COMPACT")
-    target_row <- xml_child(kable_tbody, header$row[i])
-    xml_add_child(target_row, new_row_item, .where = 0)
-  }
-
-  out <- structure(as.character(kable_xml), format = "html",
-                   class = "knitr_kable")
-
-  # Adjust for column_spec
-  if (is.null(kable_attrs$column_adjust)) {
-    table_nrow <- length(xml_children(kable_tbody))
-    # if (!is.null(kable_attrs$group_header_rows)) {
-    #   table_nrow <- table_nrow - length(kable_attrs$group_header_rows)
-    # }
-    table_ncol <- length(xml_children(
-      xml_child(kable_thead, length(xml_children(kable_thead)))
-    ))
-    kable_attrs$column_adjust$matrix <- matrix(
-      rep(TRUE, table_nrow * table_ncol), ncol = table_nrow)
-    kable_attrs$column_adjust$count <- 1
-    new_row_index <- rep(FALSE, table_nrow)
-  } else {
-    new_row_index <- rep(FALSE, ncol(kable_attrs$column_adjust$matrix))
-    kable_attrs$column_adjust$count <- 1 + kable_attrs$column_adjust$count
-  }
-  new_row_index[header$row] <- TRUE
-  kable_attrs$column_adjust$matrix <- rbind(
-    new_row_index, kable_attrs$column_adjust$matrix
-  )
-  attributes(out) <- kable_attrs
-
-  return(out)
-}
-
-standardize_header <- function(header, n_row) {
-  header_names <- names(header)
-
-  if (is.null(header_names)) {
-    return(data.frame(header = header, row = 1:length(header),
-                      rowspan = 1, row.names = NULL))
-  }
-
-  names(header)[header_names == ""] <- header[header_names == ""]
-  header[header_names == ""] <- 1
-  header_names <- names(header)
-  header <- as.numeric(header)
-  names(header) <- header_names
-  if (sum(header) < n_row) {
-    header <- c(header, " " = n_row - sum(header))
-  }
-  row_pos <- c(1, cumsum(header)[-length(header)] + 1)
-  return(data.frame(
-    header = names(header),
-    row = row_pos, rowspan = header, row.names = NULL
-    ))
-}
-
-add_header_left_latex <- function(kable_input, header, header_name, align,
-                                  width, bold, italic, full_midline = F) {
-  table_info <- magic_mirror(kable_input)
-  usepackage_latex("multirow")
-  if (!table_info$booktabs) {
-    warning("add_header_left only supports LaTeX table with booktabs. Please",
-            " use kable(..., booktabs = T) in your kable function.")
-  }
-  out <- as.character(kable_input)
-  contents <- table_info$contents
-  header_name <- escape_latex(header_name)
-  header <- standardize_header(header, length(contents) - 1)
-  header$header <- escape_latex(header$header)
-  header$header <- gsub("\\\\", "\\\\\\\\", header$header)
-  header$row <- header$row + 1
-  header$row_end <- header$row + header$rowspan - 1
-
-  # Align
-  align_row <- latex_column_align_builder(align, width, bold, italic)
-
-  out <- sub(paste0(table_info$begin_tabular, "\\{"),
-             paste0(table_info$begin_tabular, "{", align_row,
-                    ifelse(table_info$booktabs, "", "|")),
-             out, perl = T)
-  # table_info$align_vector <- c(align, table_info$align_vector)
-
-  # Header
-  ## Extra header rows introduced by add_header_above
-  if (!is.null(table_info$new_header_row)) {
-    new_header_row <- table_info$new_header_row
-    for (i in 1:length(new_header_row)) {
-      out <- sub(regex_escape(new_header_row[i]),
-                 paste0(" & ", new_header_row[i]), out)
-      cline_old <- cline_gen(table_info$header_df[[i]], table_info$booktabs)
-      cline_old <- regex_escape(cline_old)
-      table_info$header_df[[i]] <- rbind(
-        data.frame(header = " ", colspan = 1),
-        table_info$header_df[[i]]
-      )
-      cline_new <- cline_gen(table_info$header_df[[i]], table_info$booktabs)
-      out <- sub(cline_old, cline_new, out)
-    }
-  }
-  ## Base Header row
-  out <- sub(contents[1], paste0(header_name, " & ", contents[1]), out)
-  table_info$contents[1] <- paste0(header_name, " & ", contents[1])
-
-  # move existing midrules if exists
-  out_lines <- read_lines(out)
-  tbody_start_row <- which(out_lines == "\\midrule")
-  tbody_end_row <- which(out_lines == "\\bottomrule")
-  before_tbody <- out_lines[seq(1, tbody_start_row)]
-  tbody <- out_lines[seq(tbody_start_row + 1, tbody_end_row - 1)]
-  after_tbody <- out_lines[seq(tbody_end_row, length(out_lines))]
-
-  # Remove addlinespace in this case
-  tbody <- tbody[tbody != "\\addlinespace"]
-
-  midrule_exist <- str_sub(tbody, 1, 9) == "\\cmidrule"
-  if (sum(midrule_exist) > 0) {
-    existing_midrules <- which(midrule_exist)
-    tbody[existing_midrules] <- unlist(lapply(
-      tbody[existing_midrules], cmidrule_plus_one
-    ))
-    out <- paste0(c(before_tbody, tbody, after_tbody), collapse = "\n")
-  }
-
-  for (j in 1:nrow(header)) {
-    new_row_pre <- paste0(
-      "\\\\multirow\\{", -header$rowspan[j], "\\}\\{",
-      ifelse(is.null(width), "\\*", width),
-      "\\}\\{",
-      switch(align,
-             "l" = "\\\\raggedright\\\\arraybackslash ",
-             "c" = "\\\\centering\\\\arraybackslash ",
-             "r" = "\\\\raggedleft\\\\arraybackslash "),
-      header$header[j], "\\} & "
-    )
-    new_row_text <- paste0(new_row_pre, contents[header$row_end[j]])
-    out <- sub(contents[header$row_end[j]], new_row_text, out)
-    table_info$contents[header$row_end[j]] <- new_row_text
-    if (j != nrow(header)) {
-      out <- sub(
-        paste0(contents[header$row_end[j]], "\\\\\\\\\n"),
-        paste0(contents[header$row_end[j]],
-               "\\\\\\\\\n\\\\cmidrule[0.5pt](l{2pt}r{2pt}){1-",
-               ifelse(full_midline, str_count(tbody[1], " & ") + 2, 1),
-               "}\n"),
-        out
-      )
-    }
-  }
-
-  for (k in setdiff(seq(2, length(contents)), header$row_end)) {
-    out <- sub(contents[k],
-               paste0("  & ", contents[k]),
-               out)
-    table_info$contents[k] <- paste0("  & ", contents[k])
-  }
-
-  out <- structure(out, format = "latex", class = "knitr_kable")
-
-  attr(out, "kable_meta") <- table_info
-  return(out)
-}
-
-cmidrule_plus_one <- function(x) {
-  start_pos <- as.numeric(str_match(x, "\\)\\{(.*)-")[2]) + 1
-  stop_pos <- as.numeric(str_match(x, "-(.*)\\}")[2]) + 1
-  return(
-    paste0("\\cmidrule[0.5pt](l{2pt}r{2pt}){", start_pos, "-", stop_pos, "}")
-  )
-}
diff --git a/R/kableExtra-package.R b/R/kableExtra-package.R
index b0674be..a690e84 100644
--- a/R/kableExtra-package.R
+++ b/R/kableExtra-package.R
@@ -1,5 +1,56 @@
 #' kableExtra
 #'
+#' @description When we are talking about table generators in R,
+#' [knitr](https://yihui.name/knitr/)'s `kable()` function wins lots of flavor
+#' by its ultimate simplicity. Unlike those powerful table rendering engines
+#' such as [`xtable`](https://CRAN.R-project.org/package=xtable), the philosophy
+#' behind [`knitr::kable()`](https://rdrr.io/cran/knitr/man/kable.html) is to
+#' make it easy for programmers to use. Just as it claimed in its
+#' function description, "this is a very simple table generator. It is simple
+#' by design. It is not intended to replace any other R packages for making
+#' tables. - Yihui".
+#'
+#' However, the ultimate simplicity of `kable()` also brought troubles to some
+#' of us, especially for new R users, who may not have a lot of experience on
+#' generating tables in R. It is not rare to see people including experienced
+#' users asking questions like how to center/left-align a table on Stack
+#' Overflow. Also, for me personally, I found myself repeatedly parsing CSS
+#' into `kable()` for some very simple features like striped lines. For LaTeX,
+#' it's even worse since I'm almost Stack Overflow dependent for LaTeX...
+#' That's why this package `kableExtra` was created.
+#'
+#' I hope with `kableExtra`, you can
+#' - Use default base `kable()` (Or a good alternative for markdown tables is
+#' `pander::pander()`) for all simple tables
+#' - Use `kable()` with `kableExtra` to generate 90 % of complex/advanced
+#' tables in either HTML or LaTeX
+#' - Only have to mess with raw HTML/LaTeX in the last 10% cases where
+#' `kableExtra` cannot solve the problem
+#'
+#' @section Features:
+#' **Pipable syntax:** `kableExtra` is NOT a table generating package. It is a
+#' package that can "add features" to a `kable` output using a syntax
+#' that every useR loves - the [pipe](http://r4ds.had.co.nz/pipes.html).
+#' We see similar approaches to deal with plots in packages like `ggvis` and
+#' `plotly`. There is no reason why we cannot use it with tables.
+#'
+#' **Unified functions for both HTML and PDF:** Most functionalities in
+#' `kableExtra` can work in both HTML and PDF. In fact, as long as you
+#' specifies format in `kable` (which can be set globally through option
+#' `knitr.table.format`), functions in this package will pick the right way
+#' to manipulate the table be themselves. As a result, if users want to left
+#' align the table, `kable_styling(kable(...), position = "left")` will work
+#' in both HTML and PDF.
+#'
+#' @note If you found a feature on the documentation site that is not available
+#' in the version of `kableExtra` you are using, try to install the pre-release
+#' version from github. You can do so by running
+#' `devtools::install_github("haozhu233/kableExtra")`.
+#'
+#' Also, note that This package can load required LaTeX package automatically in
+#' vanilla rmarkdown. For customized rmarkdown templates, it is recommended to
+#' load related LaTeX packages manually.
+#'
 #' @importFrom stringr str_count str_split str_match str_detect str_match_all
 #' str_extract str_replace_all str_trim str_extract_all str_sub
 #' @importFrom xml2 read_xml xml_attr xml_has_attr xml_attr<- read_html