I highly recommend "Functional JavaScript" by Michael Fogus (creator of Lemonad), <a href="http://www.amazon.com/Functional-JavaScript-Introducing-Programming-Underscore-js/dp/1449360726/ref=sr_1_1?ie=UTF8&qid=1372302146&sr=8-1&keywords=functional+javascript" rel="nofollow">http://www.amazon.com/Functional-JavaScript-Introducing-Prog...</a>
Another great project:<p>Bilby: Serious functional programming library for JavaScript <a href="https://github.com/puffnfresh/bilby.js" rel="nofollow">https://github.com/puffnfresh/bilby.js</a>
Lemonad was once much larger with a wider range of functional operators. Recently most of its functions have been moved into underscore-contrib (<a href="https://github.com/documentcloud/underscore-contrib" rel="nofollow">https://github.com/documentcloud/underscore-contrib</a>). Most of my JS time lately has been spent with _.contrib, but I plan to come back to Lemonad soon and write up full docs and the like.