The book is an attempt to introduce the readers to the Polish school of scientific (or analytic) philosophy which came to be known as the Lvov-Warsaw School. Although the Polish circle of mathematical logic is well known in the world and everyone is acquainted with the achievements of its most important scholars (like Lukasiewicz or Tarski), the philosophical ideas on which that circle has grown are still quite unknown. For this reason, this collection centers on purely philosophical matters, offering a series of essays on some important scholars and topics. The papers collected in the volume are divided into two parts. The first part contains papers which relate the Lvov-Warsaw School to other philosophical movements (Brentanism, phenomenology and Marxism). The second part collects papers which focus on internal issues connected with the school.