Two timelines:London at the beginning of the 21st & London in the 17th century. Characters and story are imagined but historical events (Sabbatean movement, the pest) & philosophers are real and very well researched.I went back&forth btw loved,liked &disliked the book.But overall, I think combining history, Jewish thought&philosophy with an entertaining plot is an amazing achievement and the author rightly received the National Jewish Book Award.