We have a lot of thread with book recommendations including ones for beginners.
Most of them recommend more than one.
But I had to tell my beginner self to pick only one book to read right now it would be *Become a Living God* by E.A. Koetting
It’s the newer and better version of his older mail order course (Ordo Ascensum Aetrynalis) revamped and has video courses to go with it. It teaches you everything soup to nuts with no fluff. You can get right into any other book and know where you are with this under your belt.