[dTal]

Surely the issues of "publisher as middleman" and "book-by-subscription" are orthogonal?

[dragandj]

Yes, but the main goal of these subscriptions is to fund my work on the free open source libraries related to the book.

You get the book, AND the active development of the libraries.

[enriquto]

I would only buy the book if you put the pdf freely downloadable on your website (I systematically do that to support authors, because I love "dead trees").