Real-World functional programming has been written by Tomas Petricek and Jon Skeet.
Tomasz’s and Jon’s book is built around how to think functionally when programming and how to make best use of functional paradigm for real world scenerios. The book is written mainly for the C# programmers who would like to switch/learn more of the functional world. It also features snippets with some technical background of the ideas involved.
As the title suggests the book is not focussed on one language, instead a mix of C# and F#, and it does a great job in bringing these worlds together,which is to me best of both worlds. Although, samples are all in functional style, when the problem needs the functional beauty to express, F# takes place. This gives any .NET developer to see when to use the necessary language for a particular problem.
The book starts slowly with the functional structures, and goes to monads, and to reactive libraries. I found the language of the book clear to understand, and easy to follow. The samples in the beginning of a chapter starts with some really simple constructs, but at the end of a chapter they become more complicated, and a nice programs to reflect the idea of the chapter.
Applied functional programming is probably the most sophisticated part of the book. Some ideas mainly inspired from research papers (cited at the end) blended with modern languages and libraries and applied somewhat differently. Especially composable functional libraries and reactive functional programs were insightful and open the mind with new possibilities.
Finally, I would recommend this book whoever wants to switch to functional programming and also learn new techniques in general. Each sample is crafted well, and represent real value with its tutorial writing style.