From the description:
" Sirens of Titan is a picaresque novel which almost defies being synposized; it is an interplanetary Candide (lacking perhaps Voltaire's utter bitterness), the book follows lead character Malachi Constant, a feckless but kind-hearted millionaire as he moves through the solar system on his quest for the meaning of all existence.
Constant is aided by another tycoon, Winston Rumfoord, who with the help of aliens has actually discovered the fundamental meaning of life (the retrieval of an alien artifact with an inscribed message of greetings). With the assistance of Salo, an alien root and overseeing the alien race, the Tralmafadorians, Constant attempts to find some cosmic sense and order in the face of universal malevolence."
4.4 stars for this one. This is from relatively early in Vonnegut's career, so this may not be every reader's cup of tea. Regardless, for only 2 bucks this should be an addition to most science fiction fan's library.