It's a great and practical book, but I'd say it serves a different role than Illusion of Life. I take it from one of the other replies that it's fallen out of print :-(
For a professional animator (including e.g. video game graphics/physics programmers), absolutely. For someone who makes a career doing user interface works, it’s a bit harder to say.
At some point there was a large portion of it on YouTube but I think it’s been (quite rightly) taken down as copyright violation.
Anyway, the parts I watched were really really good.