Add a table of contents to a PDF file with pdftk

Many scanned old books come with no table of contents. And Googling how to add tables of contents usually show up less helpful advice such as “buy Acrobat”. To save myself from having to Google this stuff again, it’s time to record it here.

First, create a text file in this format:

BookmarkLevel: 1
BookmarkPageNumber: 7
BookmarkBegin
BookmarkTitle: Table of Contents
BookmarkLevel: 1
BookmarkPageNumber: 13
BookmarkBegin
BookmarkTitle: Chapter 1. Installation
BookmarkLevel: 1
BookmarkPageNumber: 13
BookmarkBegin
BookmarkTitle: Section 1. Getting the Source Code
BookmarkLevel: 2

The BookmarkPageNumber seems to refer to the “physical” page numbers instead of the “logical” ones. The page numbers don’t have to be in ascending order, so if a book containing some crazy internal reference, such as Chapter 12 requiring you to keep referencing a certain figure from Chapter 2, you can make a bookmark to jump back to it.

After finishing this step, run pdftk:

pdftk input.pdf input_toc.txt output output.pdf

And never read a long PDF without a proper table of contents any more.

References: learned the technique from here.