The author of the paper demonstrates that the term lēḇ, lit. «heart», in the Books of Ecclesiastes and Proverb embraces the following spectrum of meanings: mind, conscience, individuality, selfness (NB: Heb. libbî, «my heart», is used in the Hebrew Bible as a synonym for «I»), reflection (cf., e. g.: Eccl. 1:16), emotions and perseptions of an intellectual nature (cf., e. g.: Eccl. 2:10:»joy» and Prov. 14:10: «bitterness»), and in fact — as a synonym for man’s spirit (soul) (cf., e. g.: Eccl. 7:28). The man’s «heart» is a centre of an intellectual and cognitive activity, it acquires and stores wisdom and knowledge — in contrast to the «flesh» indulging in «foolish» pleasures (cf., e. g.: Eccl. 2: 3ff.). Sometimes the concept of «heart» indicates a higher level of the mind’s development, something a «fool» lacks (cf., e. g.: Prov. 6:32, 7:7, 9:4, etc.), and which potentially capable people should strive to «acquire» (cf., e. g.: Prov. 15:32, 19: 8).