A me le guardie! - GUARDS! GUARDS!, by Terry Pratchett (1989, UK)

Lord Vetinari has got a truly ambitious assistant. Vimes is already the captain, but the guards role is secondary. And he begins as an alcolist. Lady Sybil is a noble, immense, expert about dragons and, when a dragon, called by magic, starts ruling Ank Morpork, Vimes, Nobby, Colon, Carota the giant hero dwarf, Lady Sybil, the Orango Librarian and the small peculiar dragon named Errol have to do sth...