Just some advance warning...the price of the documentation will increase to US$39.95 when JFreeChart version 0.9.4 is released (in the next week or two).
Since documentation updates are free for one year from the date of purchase, you can avoid this price increase by buying a copy BEFORE 0.9.4 is released.
Regards,
DG
P.S. Thanks to everyone who has purchased the documentation to date. It is providing a valuable source of funding to the project. In particular, it is allowing me to spend more time on JFreeChart than would otherwise be possible.