Legal interpreters assume, inter alia, that the legislator consistently applies the concepts throughout the entire legal act, and that they do not introduce any unnecessary fragments into the text (prohibition of per non est interpretation). Do such interpreters' assumptions accurately reflect the way the legislator works? And do the persons handling the legislative process employ in their work tools with which the law will then be read? In order to find the answer to this question, the author has analyzed the applicable legislation and has undertaken socio-legal research, using the methods of text analysis, participant observation and in-depth interviews with legislators working in the Legislative Office of the Chancellery of the Sejm of the Republic of Poland. The results of his research and the conclusions derived from it are presented in the monograph titled Korespondencja dyrektyw redagowania i interpretowania tekstu prawnego. [Correspondence of the Directives for Drafting and Interpreting a Legal Text].