The first Rebus book. (I'm continuing my programme of reading these in completely the wrong order by /not/ saving this one for last.)
Competently written, if very short. Stylish, in a slightly ostentatious way that the later books aren't. Interesting to meet the characters for the first time knowing all there is to know about them already.
Major quibble: this breaks the normal mystery-story convention by making it completely impossible to figure out who the murderer is before Rebus does. (There's one clue that you could figure out, but I didn't, and it wasn't actually enlightening in the greater scheme of things anyway.)
Worth reading, anyway, and the series does only get better after this.
ISBN 0752809423. Search for this book on Wikipedia or isbn.nu.