Charles Nicholl's prize-winning 1992 study The Reckoning: The Murder of Christopher Marlowe is a richly-detailed, if highly speculative, examination of the life, career and death of Marlowe, the well-known Elizabethan poet and playwright. A fascinating reconstruction of espionage and politico-religious intrigue during the later years of Elizabeth I's reign, the book offers up a plausible if not entirely proven (or prove-able) theory about Marlowe's murder being part of a high-level court struggle.
Nicholl's done his archival research, and includes many discoveries about Marlowe as well as significant amounts of biographical material relating to others in Marlowe's political, poetical and social circles. While I think in some cases that Nicholls' aren't the only conclusions that could be drawn from the available evidence, his theories seem just as possible as any others (admittedly, more evidence may be known now than Nicholl had access to; things might have changed in the last fifteen years).
My one major quibble with this book is the lack of good citation apparatus; in a book of this type, where significant amounts of the author's credibility depends on the reliability of the evidence being cited, it is an unconscionable negligence on the part of the publisher to leave footnotes unindicated in the text, forcing the reader to guess what might be cited and then look in the back to check for it. If not for this shortcoming, I'd feel much more positive about the book. As it is, I still recommend it highly for anyone who's up for a lot of details and some good old-fashioned court intrigue.