I personally find Steele's C: A Reference Manual far more useful in day to day hacking. But, that's one of four Steele-authored language specs I look at frequently (Common LISP, Scheme, and Fortress), so I might just have carefully tuned my search methods to his writing style.
i've mentioned preferring this book over k&r here before, but as someone pointed out they do slightly different things - k&r is more about teaching how to use c.
but apart from all that, how come you get to use fortress frequently? what are you doing? is it becoming more popular? has it survived oracle?