"Guards ! Guards !" is the eighth book in Terry Pratchett's hugely popular Discworld series and is the first to focus on Sam Vimes and Ankh-Morpork's City Guard. Although the City Guard was once a fine and noble profession, it has fallen by the wayside in recent years. Once, there had been hundreds of members : as the book opens, the City's Night Watch is staffed only by Sam, Sergeant Fred Colon and Corporal Nobby Nobbs. Like the Night Watch itself, Sam has also fallen on hard times. Having started drinking to forget (it was possibly something to do with a woman), he now drinks to forget the drinking. Despite his faults, though, he's a likeable cynic who has a well-developed sense of fair play and identifies with the underdog.
Things start turning around for Sam and the Watch in "Guards ! Guards !". The force sees a dramatic rise in numbers with the arrival of Carrot Ironfoundersson. Orphaned as a baby, Carrot had been taken in by the dwarfs and raised in a gold mine. Until shortly before he left home, he didn't realise he was human - he'd always thought he was just tall for his species. His adoptive father decides it's best for Carrot to spend some time with other humans and 'manages' to secure a position for him in the Ankh-Morpork City Guard. Carrot, on his arrival, is viewed with some amazement : an actual, honest volunteer. He takes things very literally (as dwarfs tend to do), is very innocent (he wouldn't know what to do with a seamstress if one fell into his lap) and a lot of the humour comes from his utter confusion.
The problem for Sam and the Night Watch is presented by the Unique and Supreme Lodge of the Elucidated Brethren. Well, actually, the problem is its mysterious (and big-headed) Supreme Grand Master, an ambitious and manipulative individual. (The remaining members are bitter, vitriolic, small-minded, jealous, resentful and a bit stupid. As a result, they're very easy to manipulate). He's devised a Machiavellian plan that will involve the removal of the Patrician (Ankh-Morpork's tyrant) and lead to the restoration of the monarchy. Unfortunately, his plan involves the controlling of a very dangerous dragon - to that end, Brother Fingers has managed to 'acquire' De Malachite's book on summoning dragons from the Unseen University's library. For some reason, it doesn't seem to bother him that the book is badly burnt.
This is the first of the Discworld books to feature Sam and the City Guard. As a result, it's a pretty good starting point if you've never read any of the other Discworld books before and want to see what you're missing. Pratchett's books are always very funny and this one gets better as it goes along. Definitely recommended.