The Land That Time Forgot is a fantasy novel by American writer Edgar Rice Burroughs, the first of his Caspak trilogy. His working title for the story was "The Lost U-Boat." The sequence was first published in Blue Book Magazine as a three-part serial in the issues for September, October and November 1918. The complete trilogy was later combined for publication in book form under the title of the first part by A. C. McClurg in June 1924. Beginning with the Ace Books editions of the 1960s, the three segments have usually been issued as separate short novels.

バローズが描く秘境カプローナは、生命の進化を壮大に表現した実験場です。本作の核心は、原始の驚異に直面した人間が文明の皮を剥ぎ取られ、剥き出しの生存本能と対峙する瞬間の熱量にあります。著者の力強い筆致は、未知の生物が跋扈する太古の森へと読者を誘い、生命の根源的な逞しさを魂に刻み込みます。 映像版が恐竜の迫力を視覚化した一方、原作は潜水艦内の心理戦や進化の階梯を巡る思弁性に満ちています。視覚の興奮とテキスト特有の深みが交差する時、物語は人間の本質を問う記録へと変貌します。両者を味わうことで、時を忘れた地はより鮮烈な現実味を帯びて私たちの前に立ち現れるのです。