The plot of the book is two young men grow up (or end up?) on a planet. One discovered technology (in a cave) and an AI educates him how to use advanced tech. The other man is discovered by natural beings who teach him how to use magic based on nature or the earth. He ends up in a battle with the other man, pitting earth against tech.
A bit transparent plot wise but a book from my past that I'm keen to re-read.