Anything by Cleckley. It's older stuff, but definitely foundational. Also if you are looking for more current research, check out Dr Kosson's work from Rosalind Franklin U.
Thanks 🙂 Picked up Without Conscience, hopefully it'll be a good intro. Just a little worried it won't be quite technical enough, but it's short, so not a big commitment.
I know you're looking for didactic ... but in case you're interested in reading something that isn't quite didactic, The Sociopath Next Door was a really interesting book. That's also assuming you feel sociopath and psychopath are interchangeable terms. 🙂