A great reference, possibly better for DSM or GT.M users than Cache. Unfortunetly, like most reference books, there are too few real-world examples. If you've inherited an Epic or IDX or Mysis app and you're trying to figure out why %ER says :
" f i s node=$$zcrap("ept",5001) d spagcode"
This book doesn't really help much. If you're writing some M from scratch, then the book is great. If you're running Cache, just stick to COS and the Intersystems docs. Your code will be easier to read and support.