As far as I'm concerned, this is my bible. I know I'm supposed to have all the integration memorized, but I don't. My brain protests when I have to do integration. And when Mrs. Spiegel & Lau have nicely compiled all of the work of Laplace, Fourier, the Bernoullis, Euler, Taylor and all of the other dead mathematicians whose memories I, and thousands like me, hate, why not use it?
On second thought, I'm buying another one to leave at work.