This book serves three overlapping audiences:

People who'd like to learn functional programming because they want to be ready if such languages become part of the mainstream.

People who'll be working in an object-oriented language but want to use some functional programming idioms and tricks of the trade in their projects.

People with less specific goals, but who believe that learning languages that conceptualize problems and solutions in radically different ways will make them better programmers in general.

The book uses Clojure, a popular functional language that runs on the Java Virtual Machine. It contains many exercises and their solutions.

For more about what the book covers, see the sample PDF. It includes the Introduction, the first chapter, and the glossary.

The book is "feature complete", but there will be bug fixes and improvements to the explanations over the next few months.

Praise

"This book, written by Brian Marick, is important. Indeed, it may be necessary. We need something to bridge the gap between the huge population of OO programmers, and the growing need for functional programmers. I’ve seen nothing else that fills this need so well."

— From a review by Robert "Uncle Bob" Martin

"@marick is blowing my mind with #fp_oo, building OO on top of FP."

— Larry Staton Jr.

"I have an understanding of monads for the first time thanks to @marick and his awesome book"

— Dave Kincaid

"'Functional Programming for the OO Programmer' by @marick features the best introduction to Clojure I've read so far."

— Sebastian Benz

"Bought #fp_oo by @marick today. Chapter 1 is the best #clojure intro I have read"

— Adrian Mowat