Mercenary Mandarin is the account of an eccentric Victorian adventurer, William Mesny. During his time in China, he worked as a smuggler and gun runner, got imprisoned by the Taiping Rebels, and eventually landed himself a job as a general for the Qing Emperor, charged with overthrowing a Miao Rebellion in the mountains of Southwest China.
This book, written by a friend of mine, David Leffman (who has guestwritten on this site), is an excellent window into China a hundred years ago. If you are interested in China in the pre-modern era, this book is a must read. For other similar books on China, check out my list of must-reads here.