Where to begin on the errors that have propagated through so many revisions? Equations are incorrectly referenced in the text some figures have problems. See fig 8.30, p513 5th revision where the curves Xopt and Yopt appear to be switched for just one example. The best part about the book is the summary of materials and the references, which you often need.

My personal note to Mr. Koechner: Dear kind sir, please publish errata for this book. I mean no disrespect, it is the best reference of its kind. However, it could be improved substantially.