The Janissary Tree

Author Jason Goodwin has a degree in Byzantine history from Cambridge and has written a book on the history of the Ottoman Empire, so one can feel reasonably sure that much of the detail in this mystery, set in 1836 Istanbul, is probably accurate. Goodwin won an Edgar award (2007) for this book, which is the first in a series of five mysteries, and there is even a cookbook based on the series!
The Empire is in decline and the world is modernizing all around this ancient culture, so it must adapt or die. But just as the sultan is days away from announcing sweeping--and no doubt controversial--reforms, several officers from the elite New Guard are kidnapped and murdered, sending everyone's anxiety soaring. The head of the guard calls in former royal court investigator, Jashim Togalu, to solve the murders and put people's minds at rest. Maybe. And then the sultan's mother, the valide, also commands Jashim to solve the murder of one of the harem's women and the theft of the valide's jewels. Jashim lives apart because he is a eunuch, but that does not mean that passions do not still stir within him. He is observant, open minded, and uniquely capable of making himself invisible in a crowd through his stillness. As he digs deeper into the mystery, he becomes convinced that a resurrection of the disgraced and disbanded Janissaries--the former army of the Empire--is the impetus behind the murders. But can he convince the powers that be in time to stop an overthrow of the sultan? Not only the exotic locale and customs, but also the wonderful vignettes of cooking, lots of political intrigue, and a sympathetic protagonist all serve to make this an engaging read. Secondary characters, especially Jashim's friends, are also intriguing. I've already got the sequel, The Snake Stone, on hold at the library. Thanks to my friend, Joan Tyler for turning me on to this book!
I am including a glowing review from The Telegraph, and this somewhat lukewarm one from Kirkus  for the plot summaries--superior to mine!