The Cat series by Joan D. Vinge, of which Psion is the first book, was one of my favorite series in the early 2000s. I actually read the second book (Catspaw) before I read Psion, which gave me an interesting perspective on the story and the character. It also threw me backward into a different style of narrative since the second book is written in first person, and the first book is written in third. It was an awkward change and probably would have gone more smoothly if I had read them in order.
For those who are interested, this series is science fiction and follows the character of Cat, a half-human, half-alien telepath who gets mixed up in the complicated workings of the interstellar government. There are a lot of interesting things implied about this character and his origins–things that are never really explained but that add a lot of mystery. He also gets into a lot of trouble, as all the best characters do. Cat is quite rough around the edges, but he’s easy to fall in love with, and the difficulties of his early life make him quite sympathetic.