This paper pays tribute to Felix Trofimovich Mikhajlov (1930-2006), on the occasion of the publication of the third edition of his well-known book, Zagadka čelovečeskogo ja (The Riddle of the Self). Zagadka is a fine expression of the critical humanism that characterized some of the best Russian writing in the Marxist tradition. Moreover, the book provides an ingenious introduction to the philosophical framework of what in the West is called "cultural-historical activity theory." The first part of the paper is a (...) personal reminiscence about Felix, his remarkable gifts, and the friendship we enjoyed for more than 25 years. The second part returns to the themes of Zagadka and considers what resonance they have for us today, nearly half a century after its first publication. (shrink)