While I have almost no technical knowledge about the Portfolio, I still found your small e-book interesting to read. Thank you! I particularly liked the inside perspective into development processes back then (no version control, no bug tracker, using a hardware ICE, …) that one rarely gets. Also, as developer (hardware and software) I can relate to the stories about last-minute fixes and afterthoughts.
In any case, it was 3.49 $ well spent. Note for other interested readers: You probably should bring a certain level of understanding about x86 and DOS to fully appreciate the book, since at times the author goes quite deep into technical details.
PS: I wish some ex-Atari employee would write a similar book, but about the ST, TT, Falcon development.