The Alchemist's Apprentice (Venice Trilogy Series #1) Book

Duncan is such a relaxed writer. You can coast along with his plot and characters, enjoying his wit, and never once notice which words he used or how he phrased something - it just happens naturally.

It probably takes someone of my age to notice what I don't see mentioned in the comments: this is a flat-out tribute to Rex Stout. Nostradamus is Nero Wolfe - fat genius who never goes out. Alfeo is Archie Goodwin, wisecracking legman and all-round assistant. Violetta is Lily Rowan. Vasco is Lt. Rowcliff. We have people come to visit Nostradamus, and Alfeo makes sure this person gets the red chair and those people get the others ... and we have a big showdown at the end. Also, Alfeo keeps visiting people and appearing to get little information, until we see that he wasn't there for information, he was there to observe behaviour - just as Archie Goodwin usually is. Nostradamus enjoys being a step ahead of Alfeo all the way, but also enjoys watching Alfeo figure it out. There's even a really good lawyer they can turn to, and a superb chef feeding the fat man. OK, the police chiefs don't match up, and there's no Saul Panzer. But as a fan of Nero Wolfe I will say the whole thing is well done and I think Stout would have liked it.

I've been to Venice, and I'll read a book just because it's set there. Duncan throws in a few real places and several fake ones, and gives us a bit of history and gondola facts as we go along.

The extra characters are good, especially Bruno, and the plot is suitably complicated. A couple of characters are implausible, but we eventually find out why. The resolution explains everything quite well, and uses some details that were given to us quite early.

Gotta go, I need to read the next one.