This is a pre-release version of TOMORROW'S WAR and requires Force on Force to play. Shawn at Ambush Alley Games is providing a bundled version of TOMORROW'S WAR and Force on Force at the very reasonable price of $20. TOMORROW'S WAR on it's own is $15.
This PDF contains all the rules needed to play gritty, "realistic" science fiction miniatures games and includes sample vehicles, unit organizations, and four original scenarios.
I have the full beta rules - but even so I'm still bloody impressed by this PDF release!