* [Introduction to Objective Caml](http://files.metaprl.org/doc/ocaml-book.pdf)
(284 pp. text from 2008, based on Jason Hickey's course at CalTech) <!-- also at http://www.cs.caltech.edu/courses/cs134/cs134b/book.pdf -->
* [Think OCaml](http://greenteapress.com/thinkocaml/thinkocaml.pdf) (142 pp. pdf)
* [Introduction to Objective Caml](http://files.metaprl.org/doc/ocaml-book.pdf)
(284 pp. text from 2008, based on Jason Hickey's course at CalTech) <!-- also at http://www.cs.caltech.edu/courses/cs134/cs134b/book.pdf -->
* [Think OCaml](http://greenteapress.com/thinkocaml/thinkocaml.pdf) (142 pp. pdf)
-
+* [Real World OCaml](https://realworldocaml.org/v1/en/html/index.html) (510 pp. text from 2013)
+ * recommend reading [Chapters 1-4](https://realworldocaml.org/v1/en/html/a-guided-tour.html) when getting started (Chapter 4 is a bit more advanced)
+ * then [Chapter 6](https://realworldocaml.org/v1/en/html/variants.html) when learning types
+ * then [Chapter 8](https://realworldocaml.org/v1/en/html/imperative-programming-1.html) when learning about mutation (OCaml has what we call *explicit* mutation)