Tschai by Jack Vance
I have read the Tschai series more times than I can count. Whenever I want to be transported to another world, to go on a fantastic adventure I can always rely on these books (or indeed most of Vance's books). Jack Vance can describe an alien world and make it more real than your own. His descriptions of the planet and the bizarre species who occupy it seize the imagination; it as though Tschai were written by an experienced ethnographer with the story teller's gift. The varieties of human species, the towns and countryside, the clothes, customs and behaviour are all absolutely enchanting and convincing. And underneath the wild adventure there are always strange moments of illumination. The hero is bold and accomplished but also tender and sensitive. His reactions to events, his response to people in trouble, his ruminations on the nature of religion and the meaning of life really strike a chord. I am only unhappy with the ending. I really wanted the series to go on.