Books are most useful for matters that don't change very much, which would probably include most academic subjects. Programming language books are good when th

Books are most useful for matters that don't change very much, which would probably include most academic subjects. Programming language books are good when they're more general in nature (e.g. John Resig's JS book) but are less useful when learning, say, a specific library. In the latter case, online materials seem to be a better guide.