資訊檢索研究的目的在解決人類對於資訊的需求。然而，隨著不同資訊型態的出現，資訊檢索的技術亦逐漸多樣化，以適應各種型態的資訊。本文說明透過元資料進行檢索，可以適用於各種型態的資訊，故可稱之為資訊檢索核心技術。作者並探討三種不同層次的元資料：靜態權威元資料、動態權威元資料、個人化元資料，及其可能的應用方式。

　　　　　The purpose of researches for information retrieval is to fulfill the information need. The various techniques for information retrieval are proposed to adapt to the diversified information types. This paper manages to deliberate the importance of metadata and suggests that information retrieval via metadata be applied to various types of information. From this viewpoint, the technique of information retrieval via metadata could be regarded as the core technique. In addition, the author also discusses three levels of metadata: statically authority-controlled metadata, dynamically authority-controlled metadata, and user-oriented metadata.