title_body: How to create clickable table of contents in a PDF? I have many technical PDF ebooks where there are no chapters (no clickable table of contents or other means for quick navigation through a document) and therefore it's really painful to search for information without full-text search. How could I create them? I would like to just take a PDF book and generate exact structure of chapters and subchapters, like:
  
  
  Intro
  First chapter
  
  Tools you will need
  Tool XYZ
  
  Second chapter
upvoted_answer: Well, you could always buy a copy of Adobe Acrobat, which is actually designed solely for the purpose of creating and editing PDF files.
  
  Or you could import the file into Calibre, convert it to ePub format, edit the ePub to add the table of contents, then convert it back to PDF.
  
  There are other free tools for working with PDF directly. If you do a Google search, you would find this page which lists several free tools for editing or modifying PDF in various ways.