From the back cover:
Grim War is a Wild Talents roleplaying game sourcebook of superowered mutants, nefarious sorcerers, and the ordinary men and women trying to control them all.
Written by Wild Talents co-authors Greg Stolze and Kenneth Hite and illustrated by Todd Shearer, Grim War introduces a fascinating and weird new system of spirit-summoning magic. Sorcerous characters can wield fantastic power -- if they are willing to pay the price. Grim War details dozens of bizarre and sometimes terrifying spirits and the harrowing spells required to treat with them.
Grim War brings the "company rules" of Greg Stolze's Reign to the superpwoered action of Wild Talents, allowing players to join, influence or oppose a dozen fully-detailed sorcerous cabals and mutant factions. Such as...
The Xolotl Cartel, which has found smuggling far more lucrative than secret ceremonies in hidden temples, and magic far more profitable than any drug.
People of Religious Freedom, a well-meaning political action group in way over its head.
Direktive Mul, once an agency for Soviet super spies, now the first line of defense against threats from the Otherworld.
Squadron A1, the U.S. Army's famous superteam, comprised only of the most upright superheroes America has to offe3r. Honest. Would the American government lie to you?
Akrab-i-allah. Citizens Against Reductionist Genetic Obsessions (CARGO). Next Iteration. The Piccione family. Projekt Ethnologisches Literaturarchiv-Sonderabteillung. The Rational Occult Study crossdisciplinary Research Organization (ROSCRO). The School of the American Future. The Way.
Each faction has its own goals, its own secrets, and its own agenda for player characters.
An extensive chapter on the background of this fascinating world offers guidelines for playing in any point in the 20th and 21st centuries, so the players themselves can define the shape and course of the Grim War.