I am using Drupal 7.17, and have created content of type book. I want the users to be able to export it to PDF format. The pages contains images, HTML tables, HTML ordered and unordered list (ul and li). What is the best way to do this? The content styles should be preserved when exported.
You can use the Print module
This module allows you to generate the following printer-friendly versions of any node:
Printer-friendly version (webpage format) (at www.example.com/print/nid) PDF version (at www.example.com/printpdf/nid) Send by email (at www.example.com/printmail/nid) where nid is the node id of content to render.
And your choice of one of the 4 PDF libraries it supports. It does have very high memory requirements when generating PDF as previous comments have noted. It is well documented and the PDF output is fully themeable.