While I'm very grateful for your effort and while anxiously waiting for your book, I notice that in your post you mention a brand new package manager, OPAM.

Do we really need of yet another package manager? How can't OPAM scatter the community further?

Now, if I write a small library and I want to make it available to OCaml developers, I have to care about: making the source code Debian and Red Hat friendly, godi friendly, oasis-db friendly and, now, OPAM. And there are probably other systems I don't even know.

It's not a critics or a rant, but honestly I need a compass to orient myself in the jungle of package managers for OCaml, and I'm using OCaml since years, think about a novice...