The study is devoted to a little-developed problem - terminology and the nature of philosophical (epistemic) search in early Greek philosophy. The author focuses on the work of Heraclitus and Parmenides, which is considered in a broad historical and philosophical context. The study is based on a detailed analysis of the semantic field of “search” - didzesis/zetesis. The monograph reflects the modern level of criticism of fragments of early Greek philosophers; the latest achievements of Heraclitian and Parmenidean studies are discussed in detail. The author reasonably pursues the thesis about the rational nature of philosophical search in the teachings of early Greek thinkers. The book is addressed to specialists in epistemology and the history of ancient philosophy, as well as to all readers interested in philosophy.