I don't know this book. I.e. I own it but have not read it. But I know the author Robert Zimmer. He was the brightest student in a good topology class I graded for at Brandeis, taught by Mike Spivak in the late 1960's. He was so strong I used to cheat and use his homework as a template for grading the problems I myself could not do. Mike called attention to how good he was and I responded that some other students were not bad either. Mike said, "I didn't say bad, I said good." Zimmer became president of The University of Chicago in 2006.
A brief glance at this book made it seem a bit advanced and terse. I think it is safe to assume this is an authoritative work, but I cannot say how easy it is to read until I examine it more closely. I would suggest possibly preparing by reading an easier book first, maybe one by Berberian. I am inclined to vote it up highly, but cannot honestly do so without reading more of it, more leisurely.
by the way, if you wonder what number micromass likes so much, try counting the parentheses on the right end.
It would be funny to see this book next to one like dunford/schwartz. the good thing about it is its focus on the key results (& the price is right too iirc). it is definitely terse though, & has pretty steep requirements. just in the first few pages it's already got the stone-weierstrass & open-mapping theorems.