The article considers structure peculiarities of the processes of perception, memory and thinking in connection with the problem of reading and understanding texts. As at present there is no fixed definition of reading yet it has been defined in this article from the point of view of the peculiarities of its structure. It was shown that reading is impossible without understanding, perception and thinking since it includes these processes. Despite the proximity of these notions, they cannot act as synonyms. The terms understanding, thinking and perception depending on what place they occupy in the structure of the reading process are analyzed in this article. It is proved that understanding unlike perception is the result of the reading process. Reading cannot take place without perception of the text and subject matter is not always understood completely. The process of thinking unlike understanding is more self-sufficient and independent process, which is crucial for both understanding and perception.