The Saracen's Mark is a historical crime novel that shifts between Elizabethan London and the exotic city of Marrakech. It's about a physician, Nicholas Shelby, and his love interest, Bianca Merton who has an apothecary shop. I haven't read the 1st 2 books in the series but it didn't affect my enjoyment of this one, though the previous stories are referred to so it might be best to read them in order to avoid spoilers. I really enjoyed the contrast between the poor inhabitants of London living in fear of the plague; the political intrigue of Queen Elizabeth's court; and the orange-scented world of Marrakech with its markets full of spices and slaves. The details of medical knowledge and methods of the time are also fascinating. All in all it's a wonderfully written tale with an interesting plot and engaging characters.