The author is a master. I first encountered his byline when trying to debug a Makefile (that I had written!), and came across his article in DDJ (http://www.drdobbs.com/tools/debugging-makefiles/197003338). It was invaluable, because I had been stuck between using make -d and @echo "building foo now", and I hadn't wanted to admit I was actually debugging and so I needed some specialized tools. I'm sure the book is excellent.

A general comment on debugging GNU Make: there's a fork (http://bashdb.sourceforge.net/remake/) that adds interactive debugging facilities to GNU Make. Since this is a fork and not a reimplementation, it's 100% compatible. Much nicer than "make -d" generally.

Yeah, but it's based on an old version of Make; we're on to 4.1 now, it's still based on 3.82.

True. You're unlikely to be using anything that's in 4.1 but not in 3.82, however. I wish the remake stuff would get merged into the main tree, but there're probably political issues there, or something.