2001 · ソースブック（プレイを拡張するルール／オプション）
Primal Codex
A d20 roleplaying supplement focused on primitive-themed settings, drawing on research and folklore from ancient Africa, Australia, Polynesia, and the Americas. It provides adaptable material for races, cultures, religions, lands, languages, and other campaign elements, with details kept intentionally open so groups can expand or alter them. The content also draws on biology, anthropology, and related sources, while prioritizing rules and setting tools over standard background entries.
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。