OCalm
OCaml is an industrial strength programming language supporting functional, imperative and object-oriented styles.
Site: http://www.ocaml.org/
Books
Unix System Programming in OCaml
This is an excellent book on Unix system programming, with an emphasis on communications between processes. The main novelty of this work is the use of OCaml, instead of the C language that is customary in systems programming. This gives an unusual perspective on systems programming and on OCaml.
Real World OCaml
This hands-on book shows you how to take advantage of OCaml’s functional, imperative, and object-oriented programming styles with recipes for many real-world tasks.
The OCaml System: Documentation and User's Manual
This the official User's Manual. It serves as a complete reference guide to OCaml. Updated for each version of OCaml, it contains the description of the language, of its extensions, and the documentation of the tools and libraries included in the official distribution.
Think OCalm
How to Think Like a Computer Scientist is an introductory programming textbook based on the OCaml language. It is intended for newcomers to programming and also those who know some programming but want to learn programming in the function-oriented paradigm using OCaml.
Using, Understanding, and Unraveling OCaml
This book describes both the OCaml language and the theoretical grounds behind its powerful type system.