curses is a hideous library in terms of function and variable naming, representing a genuine low point in the already not-stellar track record of C codebases of the late '70s/early '80s. It's also, however, a small and conceptually straightforward one; there's little a book can say about it that the man pages don't, and little that Programming with curses does. You may prefer to have an off-line reference, but there are cheaper options.
The main value of this book, then, is that its title is funny if you pretend not to know what curses is, and that's exactly why I bought it.