IMO, the more important book (as a HT-related tool for the kind of stuff in knifemaking) is the ASM Atlas of Isothermal Transformation. It's got the IT (TTT) charts for hundreds of alloys along with some other useful info for each, such as chemistry, etc, arranged for easy reference.
If you don't know how to use these charts or need the basics on how to apply that info and do martempering, marquenching, isothermal quenching, or any of the other basic techniques, a handy primer is Metallurgy Fundamentals, Brandt, Goodheart-Wilcox.
These two will get you going.
I have probably 8 ft. of shelf full of ASM books. The atlas is by far the most useful to me. I would probably buy the book if the price was right. I would not pay dearly for that particular one.