4/series. Imagine the imperious, mercurial Elizabeth Tudor as sleuth: author Harper makes it believable in this very successful series. As with all skilful plots, this one isn't precisely what it seems, nor are many of the characters, all varied and fascinating. Harper has mastered the intriciacies of court life in the late 1500's, and we are treated to a number of interesting glimpses, including the Royal Wardrobe that was so enormous that it had to be separately housed in a former-monastery (near today's Blackfriar's Tube stop!). If period details absorb you, you'll love this series. It's a 4.