The Time Traders

If it is possible to conquer space, then perhaps it is also possible to conquer time. At least that was the theory American scientists were exploring in an effort to explain the new sources of knowledge the Russians possessed. Perhaps Russian scientists had discovered how to transport themselves back in time in order to learn long-forgotten secrets of the past. That was why young Ross Murdock, above average in intelligence but a belligerently independent nonconformist, found himself on a hush-hush government project at a secret base in the Arctic.

Chicago Tribune

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