Pohl, Frederik and Thomas T. Thomas. MARS PLUS. [Riverdale, NY]: Baen, . Octavo, boards. First edition. A fine copy in fine dust jacket. (#91661). Price: $25.00 Add to Cart Ask a Question Add to Wish List See more items by Frederik Pohl, Thomas T. Thomas Printing identification statement for this book:"First printing, June 1994" on copyright page.