The Color of Magic by Terry Pratchett (1983, ISBN 978-0-06-085592-5)
 

 Wikipedia says-- The Colour of Magic is a 1983 fantasy comedy novel by Terry Pratchett, and is the first book of the Discworld series.

 

Further--  The story takes place on the Discworld, a planet-sized flat disc carried through space on the backs of four gargantuan elephants – Berilia, Tubul, Great T'Phon and Jerakeen – who themselves stand on the shell of Great A'Tuin, a gigantic star turtle. The surface of the disc contains oceans and continents, and with them, civilizations, cities, forests and mountains. 

 

This is a fun novel. I enjoyed it very much. Hope to read more in the series.

Purchased at Powell's on (unknown ) for 6.98$