D. S. LUTZ attempts to link the theoretical premises underlying one important aspect of constitutional design, the amendment process, with the empirical patterns revealed by a systematic, comparative study of constitutions. He begins with a brief overview of the theoretical assumptions that underlay the formal amendment process when it was invented, identify a number of theoretical proposition concerning the amendment process, and then look for patterns in the use of the amendment process. The purpose of this paper is to examine such a cross-national empirical analysis developed by LUTZ and discuss his theory of constitutional amendment.