For me, this incredible book is as near to perfection as I am ever likely to see. This could be my template for a five-star book - a definite masterpiece. Having just read another classic that also pushed onto my all-time favorites list - Bulgakov's The Master and Margarita - I was struck by just how completely the great writers can take possession of your mind and your life. All they require is some of those too-brief periods when you can sit and really concentrate on their wondrous stories and skills. 
 I found quite a few really excellent reviews of this book below. I will focus here on aspects that were not so frequently covered in other reviews. 
 First, a personal note about GR friends. I have reached a point, in my year-plus on this site, where nearly every book I read was unknown to me until I read a favorable review by a friend. In this case, Cindy liked The Dervish House and recommended it for fans of The Windup Girl. That would be me (I couldn't put it down, and would definitely re-read it). And the comparison is certainly apt, as several reviewers have noted. 
 But for all my admiration of The Windup Girl, I think this book is written with much more depth and skill. It is certainly more sensitive in its treatment of female characters. Another book that would draw comparisons is Thomas Pynchon's Gravity's Rainbow, which I read many years ago and was also a major influence at that time. But again, I think that The Dervish House is a superior read. Both books sparkle with dense, twisting prose. Both combine history, science, and human emotion with adventure and a rapidly evolving storyline. In both cases, the technical mastery is dazzling, and every sentence is tightly structured, with multiple layers of meaning and insight. But here, the writing is very full of human life, with characters that seem both real and worth caring about. Religious and spiritual traditions play a critical role here, and add greatly to the impact of the story. Pynchon's masterpiece, by comparison, is arid and impersonal, and in that sense the reader (this one, anyway) is not personally drawn into the story. 
 This is not a book for those who want a quick or light read. The writing is very readable but dense, with an almost metronomic precision that must be followed carefully to be understood. Moreover, it is loaded with detail about Turkish history and culture that will not be familiar to many readers (including me). I am perfectly okay with this - I like to take a book on its own terms, and enjoy it (or not) by how well it succeeds in the world it creates. For me, the great writers always teach, and learning from them is one of the great joys of reading. 
 More than anything else, this book read for me like a felt-life guide through the past and near future of Istanbul. After reading it, I didn't want to live there, but I certainly felt the value of understanding its complexities, and the central place it occupies in so many cultural histories. These historical lessons and perspectives alone would have made it a top book selection on my shelf. 
 But there is so much more here. In fact, the fluid integration of extremely complex themes is what I found most amazing about this work. It really pushed all of my intellectual and spiritual buttons, since the themes are both universal and a big part of my own everyday thinking, when I contemplate this crazy world and my place in it. The level of skill required to seamlessly integrate these deeper themes, in a ripping good story, was simply stunning. I found myself shaking my head in amazement, and I certainly didn't want it to end. 
 ***The following contains fairly specific hints about plot elements, but no direct spoilers (I think). 
 For example - what is really important for a meaningful and rewarding life? Each of the major characters has a different set of answers, and each of their stories is brilliantly written from his/her everyday point of view. These points of view are often expressed in extremely effective dialogue (and several gripping monologues), all very tightly woven into the storyline. It's all about money for one - the deal, the river of currency flows, and the technical skill to grab a handful with perfect timing as it slides by. For another, a life of drug abuse and casual meanness is transformed, by a critical moment, to religious visions that have complex origins and multiple interpretations. The question of just what these visions represent becomes a fascinating element of the story. For a third, a life of sensory deprivation becomes a detective chase and a thrilling but dangerous adventure. All of these perspectives are presented as narratives with incredible skill, by a great writer at the top of his game. 
 A second example - what does the future hold for the human species? In most dystopian worlds, human actions have made the home planet all but uninhabitable, while those most responsible live largely in denial of their misdeeds, and above the resulting fray. Where does it all lead? The Windup Girl looks at this issue and presents a terrifying and cruel future that is, perhaps, inevitable given the path we are now on. By contrast, The Dervish House takes a much more subtle and nuanced approach. The toll of human excess is everywhere in evidence, and there are plenty of reasons to look back in anger at past abuses. But the characters generally don't do this. They simply live in the world as it is. Yes, it is unbearably hot, and everyone knows this is very bad but they get on with it. Yes, nanotechnology has terrifying potential for both intended and unintended calamity. But nanobots and nanodrugs play important and workmanlike roles in everyday life, a bit like the smartphones that many of us rely on today. In this book, the future is a work in progress. 
 I was left shaking my head and smiling at the sheer artistry of it all. And anxious to move through my long TBR list of recommendations by GR friends. Their collective intelligence about great books is my great pleasure. For The Dervish House, my highest recommendation.