It's too early to publish exact book sales the way I did for the first edition. I have to wait a couple of months for my first Royalty reports and payments. I also think it's too early to see iText in Action in the Top 10 of Retail Bestsellers, but I have some Bestsellers lists regarding the on-line sales:
As you can see, I'm in good company.
As for the Book signing session at Devoxx, I only had to sign 10 copies. That's not much (much less than 4 years ago), but then again it was to be expected. The people at the Bookstore Booth complained that it was very hard to compete with Amazon, and even with the Manning Early Access Program.
I've heard two excuses at Devoxx: (1) I can only buy a limited number of books, because I can't carry that much luggage, and (2) I already have the first book, and that's sufficient for me... That may very well be, but the second book contains a lot of functionality that wasn't available when the first book was written. Readers of the first book won't be disappointed once they start reading the second edition.
For more info, read what the reviewers say!