I don't remember where I saw this book first mentioned, but it had seemed interesting enough that I had put it on my "want to read" list. After a few months I finally got around to it, and it was really good.
Bagoas is a Persian boy whose family is killed when he is only 10 due to political upheaval, intrigue and betrayal. Bagoas is the only one to survive, due to his good looks he is sold to be an eunuch. After just a few years, he is taken into the court of the Persian ruler, King Darius. After Darius' death, Bagoas is given to Alexander the Great, and soon becomes not only a member of his household, but close to Alexander's heart. He is part of Alexander's life during his last years, including his India campaign.