diff --git a/Gemfile b/Gemfile
index 2af3ea2..16a4a5a 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,18 +1,18 @@
 source 'https://rubygems.org'
 
-gem 'rake'
-gem 'asciidoctor', '1.5.6.1'
+gem 'rake', '13.0.3'
+gem 'asciidoctor', '2.0.12'
 
-gem 'json'
-gem 'awesome_print'
+gem 'json', '2.5.1'
+gem 'awesome_print', '1.9.2'
 
-gem 'asciidoctor-epub3', :git => 'https://github.com/asciidoctor/asciidoctor-epub3'
-gem 'asciidoctor-pdf', '1.5.0.alpha.16'
+gem 'asciidoctor-epub3', '1.5.0.alpha.19'
+gem 'asciidoctor-pdf', '1.5.4'
 gem 'asciidoctor-pdf-cjk', '~> 0.1.3'
 gem 'asciidoctor-pdf-cjk-kai_gen_gothic', '~> 0.1.1'
 
-gem 'coderay'
-gem 'pygments.rb'
-gem 'thread_safe'
-gem 'epubcheck'
-gem 'kindlegen'
+gem 'coderay', '1.1.3'
+gem 'pygments.rb', '2.2.0'
+gem 'thread_safe', '0.3.6'
+gem 'epubcheck-ruby', '4.2.5.0'
+gem 'html-proofer', '3.18.8'
diff --git a/README.asc b/README.asc
index ce7b6e9..b190779 100644
--- a/README.asc
+++ b/README.asc
@@ -14,22 +14,46 @@
 
 == 책 생성 방법
 
-직접 e-book을 생성하려면 Asciidoctor를 이용합니다.
-다음과 같은 명령을 실행하면 _아마도_ HTML, Epub, Mobi, PDF 버전의 책을 생성할 수 있을 것입니다.
+아래의 방법이 아니라도 직접 Asciidoctor 도구를 사용하여 e-book을 만들 수도 있습니다.
+예전에 Kindle 형식의 e-book인 .mobi 파일을 만들 수 있었지만 현재는 Kindle 형식의 e-book을 생성하지는 않습니다(https://github.com/progit/progit2/issues/1496[관련 1496 이슈]).
+다음과 같은 명령을 실행하여 HTML, Epub, PDF 버전의 책을 생성할 수 있습니다.
+`asciidoctor-pdf-cjk-kai_gen_gothic-install` 명령은 PDF에 포함시킬 한국어 글꼴을 다운로드 하는 명령입니다.
 
 ----
 $ bundle install
+$ asciidoctor-pdf-cjk-kai_gen_gothic-install
 $ bundle exec rake book:build
 Converting to HTML...
  -- HTML output at progit.html
 Converting to EPub...
  -- Epub output at progit.epub
-Converting to Mobi (kf8)...
- -- Mobi output at progit.mobi
 Converting to PDF...
  -- PDF output at progit.pdf
 ----
 
+모든 형식의 e-book을 생성하지 않고 특정 형식(HTML, EPUB, PDF)만을 생성할 수도 있습니다.
+다음 명령은 HTML, EPUB, PDF 필요한 내용만을 생성하는 명령입니다:
+
+HTML 형식 e-book을 생성하려면:
+
+----
+$ bundle exec rake book:build_html
+----
+
+EPUB 형식 e-book을 생성하려면:
+
+----
+$ bundle exec rake book:build_epub
+----
+
+PDF 형식 e-book을 생성하려면:
+
+----
+$ bundle exec rake book:build_pdf
+----
+
+현재 한글 PDF 빌드에 대한 문제를 #114 에서 해결하고 있습니다.
+
 == 새로 이슈 만들기
 
 새로 이슈를 만들기 전에 버그 관리 시스템에 비슷한 이슈가 이미 등록되었는지 먼저 확인해보시기 바랍니다.
diff --git a/Rakefile b/Rakefile
index 316e1eb..a0bf580 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1,40 +1,138 @@
 namespace :book do
-  desc 'build basic book formats'
-  task :build do
+  def exec_or_raise(command)
+    puts `#{command}`
+    if (! $?.success?)
+      raise "'#{command}' failed"
+    end
+  end
 
-    `cp progit.asc progit.asc.bak`
-    begin
-      version_string = ENV['TRAVIS_TAG'] || `git describe --tags`.chomp
-      if version_string.empty?
-        version_string = '0'
+  # Variables referenced for build
+  version_string = ENV['TRAVIS_TAG'] || `git describe --tags`.chomp
+  if version_string.empty?
+    version_string = '0'
+  end
+  date_string = Time.now.strftime('%Y-%m-%d')
+  params = "--attribute revnumber='#{version_string}' --attribute revdate='#{date_string}'"
+  header_hash = `git rev-parse --short HEAD`.strip
+
+  # Check contributors list
+  # This checks commit hash stored in the header of list against current HEAD
+  def check_contrib
+    if File.exist?('book/contributors.txt')
+      current_head_hash = `git rev-parse --short HEAD`.strip
+      header = `head -n 1 book/contributors.txt`.strip
+      # Match regex, then coerce resulting array to string by join
+      header_hash = header.scan(/[a-f0-9]{7,}/).join
+
+      if header_hash == current_head_hash
+        puts "Hash on header of contributors list (#{header_hash}) matches the current HEAD (#{current_head_hash})"
+      else
+        puts "Hash on header of contributors list (#{header_hash}) does not match the current HEAD (#{current_head_hash}), refreshing"
+        `rm book/contributors.txt`
+        # Reenable and invoke task again
+        Rake::Task['book/contributors.txt'].reenable
+        Rake::Task['book/contributors.txt'].invoke
       end
-      text = File.read('progit.asc')
-      new_contents = text.gsub("$$VERSION$$", version_string).gsub("$$DATE$$", Time.now.strftime("%Y-%m-%d"))
-      File.open("progit.asc", "w") {|file| file.puts new_contents }
+    end
+  end
+
+  desc 'build basic book formats'
+  task :build => [:build_html, :build_epub, :build_pdf] do
+    begin
+        # Run check
+        Rake::Task['book:check'].invoke
+
+        # Rescue to ignore checking errors
+        rescue => e
+        puts e.message
+        puts 'Error when checking books (ignored)'
+    end
+  end
+
+  desc 'build basic book formats (for ci)'
+  task :ci => [:build_html, :build_epub, :build_pdf] do
+      # Run check, but don't ignore any errors
+      Rake::Task['book:check'].invoke
+  end
+
+  desc 'generate contributors list'
+  file 'book/contributors.txt' do
+      puts 'Generating contributors list'
+      `echo "Contributors as of #{header_hash}:\n" > book/contributors.txt`
+      `git shortlog -s | grep -v -E "(Straub|Chacon|dependabot)" | cut -f 2- | column -c 120 >> book/contributors.txt`
+  end
+
+  desc 'build HTML format'
+  task :build_html => 'book/contributors.txt' do
+      check_contrib()
+
+      puts 'Converting to HTML...'
+      `bundle exec asciidoctor #{params} -a data-uri progit.asc`
+      puts ' -- HTML output at progit.html'
+
+  end
+
+  desc 'build Epub format'
+  task :build_epub => 'book/contributors.txt' do
+      check_contrib()
+
+      puts 'Converting to EPub...'
+      `bundle exec asciidoctor-epub3 #{params} progit.asc`
+      puts ' -- Epub output at progit.epub'
+
+  end
 
-      puts "Generating contributors list"
-      `git shortlog -s | grep -v -E "(Straub|Chacon)" | cut -f 2- | column -c 120 > book/contributors.txt`
+  desc 'build Mobi format'
+  task :build_mobi => 'book/contributors.txt' do
+      # Commented out the .mobi file creation because the kindlegen dependency is not available.
+      # For more information on this see: #1496.
+      # This is a (hopefully) temporary fix until upstream asciidoctor-epub3 is fixed and we can offer .mobi files again.
 
-      puts "Converting to HTML..."
-      `bundle exec asciidoctor progit.asc`
-      puts " -- HTML output at progit.html"
+      # puts "Converting to Mobi (kf8)..."
+      # `bundle exec asciidoctor-epub3 #{params} -a ebook-format=kf8 progit.asc`
+      # puts " -- Mobi output at progit.mobi"
 
-      puts "Converting to EPub..."
-      `bundle exec asciidoctor-epub3 progit.asc`
-      puts " -- Epub output at progit.epub"
+      # FIXME: If asciidoctor-epub3 supports Mobi again, uncomment these lines below
+      puts "Converting to Mobi isn't supported yet."
+      puts "For more information see issue #1496 at https://github.com/progit/progit2/issues/1496."
+      exit(127)
+  end
+
+  desc 'build PDF format'
+  task :build_pdf => 'book/contributors.txt' do
+      check_contrib()
 
-      puts "Converting to Mobi (kf8)..."
-      `bundle exec asciidoctor-epub3 -a ebook-format=kf8 progit.asc`
-      puts " -- Mobi output at progit.mobi"
+      puts 'Converting to PDF... (this one takes a while)'
+      `bundle exec asciidoctor-pdf #{params} -r asciidoctor-pdf-cjk-kai_gen_gothic -a pdf-style=KaiGenGothicKR progit.asc `
+      puts ' -- PDF output at progit.pdf'
+  end
 
-      puts "Converting to PDF... (this one takes a while)"
-      `bundle exec asciidoctor-pdf -r asciidoctor-pdf-cjk-kai_gen_gothic -a pdf-style=KaiGenGothicKR progit.asc 2>/dev/null`
-      puts " -- PDF output at progit.pdf"
+  desc 'Check generated books'
+  task :check => [:build_html, :build_epub] do
+      puts 'Checking generated books'
+
+      exec_or_raise('htmlproofer --check-html progit.html')
+      exec_or_raise('epubcheck progit.epub')
+  end
 
-    ensure
-      `mv progit.asc.bak progit.asc`
+  desc 'Clean all generated files'
+  task :clean do
+    begin
+        puts 'Removing generated files'
+
+        FileList['book/contributors.txt', 'progit.html', 'progit.epub', 'progit.pdf'].each do |file|
+            rm file
+
+            # Rescue if file not found
+            rescue Errno::ENOENT => e
+              begin
+                  puts e.message
+                  puts 'Error removing files (ignored)'
+              end
+        end
     end
   end
+
 end
 
 task :default => "book:build"