Time Traders — Andre Norton

"If it is possible to conquer space, then perhaps one can also conquer time. To test this theory Ross Murdock finds himself transplanted to the North Pole to participate in a top secret project. It is suspected that Russian scientists have discovered how to transport themselves back to prehistoric times in order to learn long forgotten secrets. Ross successfully assumes the role of a trader during the Bronze Age ...

Andre Norton is a superb storyteller whose skill draws the reader completely into a fantastic other world of transposed time." -- Chicago Tribune