In Eclipse Phase, Firewall is a cell-based conspiracy that fights existential threats to (trans)humanity, including things like the gray goo scenario, weapons of mass destruction, bioweapons, terrorists, rogue AIs, aliens, and so on. It's also the primary group for PCs, and Firewall is the organization's sourcebook.

Adds some new crunch, like traits, gear, and sample characters. But mostly, it's fluff. Covering things like the organization's history, how they're organized, internal factions, ongoing operations, notable locations and operatives (NPCs), and Firewall's relationships with other groups. A significant portion of the book also covers many of those other groups, including the Argonauts, hypercorps, Jovian and Titanian agencies, oligarchs, religious organizations, and the Ultimates.