Edition: Corgi, 1990
This is the seventh of Pratchett's incredibly popular Discworld novels. It is quite remarkable how the standards of the series have been kept up; in my opinion, the first novel, The Colour of Magic, is the weakest. This is in contrast to the usual deterioration of science fiction and fantasy series as the series lengthens, especially for series like the Discworld which are more groups of linked works set in a common world rather than a planned sequence.
The plot is a simple one concerning an attempt to sieze power in the city of Ankh-Morpork by summoning a dragon to terrorise the population, then arranging for a hero to kill it and be crowned king, with the plotter as power behind the throne. The plan is foiled by the generally despised city guard, described as being not so much 'rank and file' as merely 'rank'. The plot is not particularly important, acting as a springboard to Pratchett's imagination.
As usual, the book is full of great jokes and references to popular culture (I like the guards' motto: fabricati diem, punc). Altogether, a fun, worthwhile read. This is probably not news to anyone; I read recently that Terry Pratchett makes up over 50% of the science fiction and fantasy sales of a leading UK retail chain, WH Smith.