2015 · キャンペーン設定（ゲーム世界）
Revelations of Mars
This sourcebook expands Hollow Earth Expedition to a dying, conflict-ridden Mars filled with strange aliens, bizarre creatures, and vast wastelands. It supports adventures involving sky pirates, robot bodyguards, Martian nobles, and other extraterrestrial characters competing for survival, power, and earthly treasures. The book includes rules for creating robot and alien player characters, new and expanded psychic powers, Martian equipment and creatures, and details on extraterrestrial inhabitants and locations. These elements can support adventures on Mars or add an alien perspective to existing Hollow Earth games.
ソースブック（プレイを拡張するルール／オプション）スキルベース（スキルを購入または獲得）ポイント制（ポイントを割り振ってスキルや能力を得る）ダイス（主にd2/コイン）
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。