Abstract
Assuming, according to Jaspers, that the measure of truth of a philosophical system is the lifestyle of its creator as well as his ability at drawing conclusions resulting from philosophical speculation to the requirements of practical action, the question must be asked, to what extent, if at all Wojciech Słomski's book tries to recognise and name the philosophically characteristic merging of theory and practise. Despite this, it shouldn't be the superior aim of any biography, let alone the biography of a philosopher. However in the case of Professor Antoni Kępiński, the connection between theoretical views and real life holds meaning not only for judging the truth of these views but most of all for a correct understanding of them.