Fourteen-year-old Jeff Wells and his robot friend Norby are suddenly transported back to 1785 in France, where they become involved with a priceless necklace, royal politics, and the accidental creation of alternate futures for Earth.
Janet Asimov was an American science fiction writer, psychiatrist, and psychoanalyst. She originally wrote as J.O. Jeppson. She was an accomplished novelist and short-story writer who sometimes worked in collaboration with her husband, the late Isaac Asimov. Among the Asimovs' joint ventures as writers is the series of juvenile novels involving an endearing robot, Norby, and his young owner, Jeff Wells.
In this adventure, Norby and Jeff are thrust backwards in time to the French Revolution, by a replica of a necklace once worn by Marie Antoinette. But this replica turns out to be a glitchy time travel device. In truth, there are several necklaces that look much alike and eventually multiple timelines as well. Our heroes travel back to neanderthal times and forward to a distant (but false) future; they meet Benjamin Franklin, aliens and others, all in an attempt to set things right. It's a confusing plot, and not nearly as entertaining as it thinks it is.
It was while reading this book that I realized that the Norby series is really just Doctor Who for kids, with Norby standing in for the TARDIS. But the Doctor does it better.
Book 5 of the Norby series takes them on a slightly different adventure. They discover a replica of a necklace from 18th century France that is actually a device built by the Others with time travelling ability. Unfortunately, by using the device they unwittingly change history. They find themselves stuck in France in a world where the French Revolution never happened. Exciting adventures ensue as they struggle to figure out how to return time to its original track.