This is an excellent book for experienced Ruby developers to add functional programming paradigms to their toolkit. This book gives excellent examples of blocks, Procs, and lambdas and ways to use them in your existing application.

I’ve been a Rubyist for over a decade, and I still learned several new techniques and how to avoid gotchas with Procs, lambdas, and blocks. This book is also perfect for the Ruby/Rails developer who wants to feel confident when consuming or writing libraries that use Ruby’s closures. Easy to understand, interesting examples, and a solid reference.

You’ve probably called methods that take in a block, but if you’ve not written a method that takes in a block, I highly recommend this book to you. Once you’re through with the book, you’ll be able to explain how [1, 2, 3].map(&:to_s) works with confidence. I’ve always been a fan of Benjamin’s writing because every concept is always followed up by real-world examples, which makes it easier for the reader to grok the concepts being taught.

I never heard Ruby could do closures, but Mastering Ruby Closures brought me from zero to hero in just a few hours! Don’t be afraid, and take a look yourself!