Print book publishing sometimes imposes limitations, namely the number of pages that can be printed. In the case of the second edition of The iPad for Photographers, I had a solid ceiling of 260 pages. Although that was more than the first edition, there was still too much new information to fit. (A good problem to have!)
To compensate, I pulled the “Helpful Apps for Photographers” chapter out of the book and made it available as a free download here (PDF, 4.7 MB). If you purchased the ebook version of the book, the chapter is already contained in the file.