Oh, wow, that's a huge tip, Panther - thank you so much - I've just looked Zapt up on Amazon. They look terrific and I've already ordered one - I can't believe I've never come across him before.
Yes, I've read the first two Jason Goodwin books. I loved The Janissary Tree but felt the other was a little slow. It might just have been that my life was very busy at the time, loads of stress, and I wasn't in the mood.
If you've not read her, I thoroughly recommend Elizabeth Peters Set in Egypt, they gallop along and whilst the stories contain intricate murder mysteries, they are also extremely funny and usually include an element of young romance as well.