From the campaign:
Sol has a single rulebook that covers both game mechanics and discusses the world of Sol. Players are encouraged to use their imaginations; if you can think of a plausible reaction to a scenario you can try it. Want to transmute a moose into a million stinging wasps? The game mechanics will allow for that scenario. What Sol brings to the table is a new world and a game system that dispenses with complex die rolling. The game is played with a few standard six-sided die and character sheet delivering on its slogan, less rolling, more role-playing.