2006 · ソースブック（プレイを拡張するルール／オプション）
Secret Societies
A roleplaying game supplement about cults, conspiracies, and secret societies. It details six real-world organizations, examining each from fantasy, modern, and futuristic perspectives, with d20 statistics and rules for using them in play. The book also includes six prestige classes, brief profiles of more than 25 additional societies, guidance on incorporating secret organizations into a campaign, and rules for creating original societies.
スキルベース（スキルを購入または獲得）属性／ステータス制（STR、CON、PERなど）レベル制（XPを獲得してレベルアップ）
ゲーム情報（人数、プレイ時間、対象年齢、クレジット）の出典：BoardGameGeek。