From publisher blurb: FOUR AGAINST MARS is an atomic-age, science-fiction, pen-and-paper game. Using the FOUR AGAINST DARKNESS popular system, you will play solo or coop missions against alien invaders in a small town. Battle Martians, Venusians, Reptilians, Zeta-Reticulans and their monsters. Available characters include scientists, survivalists, combat specialists, criminals, espers, medics, and civilians. You just need pencil, paper, polyhedral dice, and plenty of imagination. This is a complete, stand-alone game. No other books are required. NO MINIATURES NEEDED.