Without giving away any twists, what’s the cleverest mystery/detective novel you’ve ever read?

For me, Agatha Christie’s Death on the Nile is a masterpiece of misdirection. The plot is expertly crafted to wrongfoot the reader.

On a totally different tack, Janice Hallett’s The Appeal uses its format of emails, texts and internet ephemera to construct to hide more than one mystery in plain sight- the murder at the centre of the book isn’t even the main case solved. I’ve read a few of her other books and she’s so good at playing with this format, which offers loads of wiggle room for the characters to pull the wool over the reader’s eyes.