The paper concerns life and scientific achievements of Maria Kokoszyńska-Lutmanowa (1906–1981) who was a significant logician, philosopher of language and epistemologist belonging to the second generation of the Lvov-Warsaw School. She is mostly known as the author of the important argumentation against neopositivism of the Vienna Circle as well as one of the main critics of relativistic theories of truth. The article is divided into five sections: 1. Life, 2. Main papers, 3. Views, 4. Pupils, 5. Summary, 6. References.