Ah, there's a mundane explanation for why the Pal Benko book is so good. I found this at Chess Cafe:
IM Jeremy Silman (the "Sil" in Siles Press) came to know and admire Benko in the 1990s, and conceived the notion of producing an ideal biography, one that would "demonstrate my own vision of how such a book should be presented." Incontrast to the common run of instant books and carelessly assembled rehashes, Silman's project took five years, and the results are impressive.
The book was intended as an example to chess presses in general. Meanwhile, Presidio Press seems to be getting into a similar game with The Civil War Experience 1861-1865.The book includes slip-covered document facsimiles and an audio tape. But $50 for a 64-page coffee-table book?