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.