The purpose of this paper is to survey the theoretical literature on wealth transfer taxation. The focus is normative: we are looking at the design of an optimal tax structure from the standpoint of both equity and efficiency. The gist of this survey is that the optimal design crucially depends on the assumed bequest motives. Alternative bequest motives are thus analyzed either in isolation or combined. Even though there are as many results as models and as many models as combinations of bequest motives, the general conclusion is that the case for a zero taxation of inheritance is very weak.