This book is for programmers who already know C++ (including the language syntax, STL containers, and elements of templates) and who want to add more tools to their toolkit. You don't need to know anything about functional programming to read the book; we took care to explain every idea in a clear and practical manner.
You do, however, need to be curious about the set of tools coming from the world of functional programming. A hefty dose of experimentation will help you to make the most of this book, so I encourage you to play around with the code and to let us know what you find.