I read this novel around the '82/'83 timeframe. The general theme is that a small boy, about 6 or 7 years old, with some type of powers is pulled into a different dimension by a mentor/guardian "leader" (not human or something the boy's mind can only "see" or had the power to call up). In that dimension, the world has a strict structure where everyone does the exact same thing...one "scene" is with a group of boys all bouncing balls at the same pace where the balls are hitting the ground at the same time, reaching the boys' hands at the same time etc. One boy is out of "sync" and even manages to lose control of the ball; it goes rolling away. Later in the book the boy with the powers sees the other in a chamber, bouncing the ball, being essentially reprogrammed. It goes on to where the boy's father, who was kidnapped years before and before the boy had any memory of him, is freed and they make their way back to their own dimension with the help of this non-human guardian. I've been mulling this one over for a long time trying to remember the title. I can see the book cover picture...a man and a boy, backs turned to the reader and holding hands, are walking into what looks like multiple rings...sort of like the rings that form on the water when something is dropped in. Memory is thinking the cover colors are in black, blue and white.