Guards! Guards! by Terry Pratchett
The 8th book in the Discworld series by Terry Pratchett, GUARDS! GUARDS! introduces readers to the main characters of The Night Watch - Sam Vimes, Fred Colon, Nobby Nobbs, Carrot Ironfoundersson (diversity quotas don't hit until a bit later in the series, so there are a lot more to come). The Night Watch is generally regarded as a bunch of no-hopers, wandering about during the night, ringing bells and walking backwards quickly from anything slightly dodgy just in case some policing might be called upon. But new recruit Carrot, a 6'6" tall "dwarf" recently arrived in the Watch, has memorised the entire book of Laws and Ordinances of the Cities of Ankh and Morpork and he's a very serious young chap when it comes to doing the job he's taken an oath to do (okay so he gave himself the oath because there's fat chance Nobby or Colon are going to think of it, but you get the idea).
Carrot's enthusiasm for the job is just the tonic for Commander Sam Vimes who's been going under with the weight of the idiot factor he's been carrying for a while now, but the summoning of a dragon by the Unique and Supreme Lodge of the Elucidated Brethern of the Ebon Night, with a view to overthrowing the Patrician (who is not best pleased at this) and the installation of a puppet king (although not all the Brethern are clear on this), is just the ticket for Sam Vimes and Carrot to weigh in with some serious policing, followed reluctantly and somewhat haphazardly by Colon and Nobbs. And it doesn't hurt that Sam Vimes meets Sybil Ramkin along the way. Sybil, breeder of swamp dragons, possessor of pots of money and member of one of the oldest and noblest families around, is an unlikely love interest, but then, to be fair, so is Vimes.
Book 8 and the whole Discworld is really starting to develop form, function and character. And for those of a visually minded reading capacity, a bit of an odour, what with swamp dragons and the river... but I digress. Listening to this series is still a thing of joy, love hearing the jokes as I'm going about day to day stuff (particularly love the honks of laughter from my partner who is often listening from another room). And Nigel Planer's reading of these books for the series on Audible is an absolute standout.
Long believed extinct, a superb specimen of draco nobilis ("noble dragon" for those who don't understand italics) has appeared in Discworld's greatest city. Not only does this unwelcome visitor have a nasty habit of charbroiling everything in its path, in rather short order it is crowned King (it is a noble dragon, after all...). How did it get there? How is the Unique and Supreme Lodge of the Elucidated Brethren of the Ebon Night involved? Can the Ankh-Morpork City Watch restore order – and the Patrician of Ankh-Morpork to power?
Magic, mayhem, and a marauding dragon...who could ask for anything more?