I'm hoping someone here can help identify or point me to a good resource for identifying a science fiction novel for a library patron. Here are the details he remembers:
He read the book during a local blizzard of 1978, so it would be published that year or earlier.
The title may have mentioned something about infinity or light.
The protagonist could travel between dimensions at will; and light or "white light" was either a triggering mechanism or some kind of component.