The Colour of Magic — Terry Pratchett

DISCWORLD --
perched on the backs of four cosmically gargantuan elephants (who themselves are traveling the intergalactic void atop a giant sea turtle)--is a place where anything can happen.

And it does when Twoflower, a naive insurance salesman turned tourist, makes the mistake of selling fire insurance to an arson-prone innkeeper. One burning town later, Twoflower and his amazing, sentient Luggage--which follows him everywhere on its hundreds of little feet--find themselves rescued by the inept wizard Rincewind, who is only too happy to turn tour guide as long as the gold flows free. And off this mismatched threesome go on an incredible adventure in the wildest realms of fantasy!