The sellers description of what this book covers reference cryogenic freezing is ambiguous. If I had known the book only covered the cryo freezing of food and designing and using the equipment used in that process I would not have purchased it. I began to read the book only to discover this, much to my disappointment. I was looking for reference material regarding Cryogenic treating of steels and other materials. This isn't that. I gave the book four stars because, while it wasn't what I wanted, it covers its topic in a well written manner.If you need a manual on the processing of frozen foods and equipment use, this book covers that in an authoritative and professional manner. The description just said "cryogenic freezing of materials". Materials would denote things other than food. This will just wind up on the reference shelf in the study.