Shantaram by Gregory David Roberts, who was formerly one of Australia's Most Wanted men following his escape from prison in the 1980s. This book is an account of his life as a fugitive when he makes it to Bombay and everything that happens afterwards: life in the slums where he deals with fires and cholera outbreaks, rescuing prostitutes from bordellos, trying to stop a serial killer, sorting out murderous Nigerians after a dodgy deal, working as street soldier, enforcer and smuggler for the Bombay Mafia and becoming a gunrunner in Afghanistan. And that's just scratching the surface of its 900-odd pages.
If there's only one book you read this year, make sure it's this one.