Unexpected. I like the way that there is a lot of learning and exposition that doesn’t feel forced or arch at any point. The whole ‘writing with fixed vocabulary’ constraint is gloriously unnecessary and fun as is the 90 day window. He is writing whatever he wants, and doing it really well - good luck to him. The close third person following of Rex is a bit of a sledgehammer way to produce the element of whodunnit, but it doesn’t feel like cheating. It’s interesting that he becomes a more complex and less likeable character as the book comes to an end. I’ll certainly read the sequels.