2003 · ソースブック（プレイを拡張するルール／オプション）
Earth Companion
This sourcebook details the New Earth Commonwealth and its Colonial Expeditionary Force, a major power in the Heavy Gear universe. It covers the history, culture, geography, and daily life of 62nd-century Earth, along with the CEF’s organization, strategies, uniforms, medals, and procedures. The book also includes characters, equipment, fighting vehicles, and fleet information for the Commonwealth and its gene-engineered military forces.
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。