In his upcoming book "Parallel Worlds" theoretical physicist Michio Kaku, explores the ramifications of the M-Theory which aims at unifying Einstein's theory of general relativity and quantum mechanics. "Are there alternate universes? Is time travel possible? What are wormholes?" are some of the questions he will address.  While Dr. Kaku is a noted contributor to the string field theory, he is also considered an expert at making some of the most complex physics concepts understandable to a wide audience.  Dr. Kaku has authored 9 books including "Beyond Einstein" and "Hyperspace". He hosts "Explorations in Science" a weekly nationally syndicated radio program.