Instruct: Classify Amazon reviews into positive or negative sentiment
Query: very many formulas

Actually I was hoping to get a practical guide to determine how to choose a regenerator for a practically workable Stirling engine.I was a little bit disappointed to see that this book is full with an incredible amount of complicated formulas. As a practical man (and not a very skilled mathematician) this book was not very useful to me.So my conclusion is: If you are not afraid of big formulas and like to REALLY know everything about regenerator theory, this might be your book.If you want to make a Stirling engine for yourself and want to check which regenerator you need for that purpose: I hope you'll find a more suitable book.