u/HarlowTellsTime

My dad read this book in the 80s, in Brazil, but is unsure of when it was written & whether he read it in English or in Portuguese - 90% sure it was in English tho. He is almost sure this is the general plot but remembers few other details besides that the twin didn't want to give up the newfound power.

He would have been in college so it's a fiction book for adults. It was hardcover.