In this paper I claim that the goal of mapping and sequencing the human genome is not wholly new, but rather is an extension of an older project to map genes, a central aim of genetics since its birth. Thus, the discussion about the value of the HGP should not be posed in global terms of acceptance or rejection, but in terms of how it should be developed. The first section of this paper presents a brief history of the project. (...) The second section distinguishes among four kinds of issues relevant to an evaluation of the HGP: those economic and organizational issues related to the feasibility of the project; the ethical questions arising in the development of the project and the application of the data gathered; the empirical issues relevant to the scientific value of the project; and conceptual issues like reductionism and determinism relevant to understand the nature and scope of the project. In a third section, I analyze in detail whether the HGP and, more generally, molecular biology is reductionistic. (shrink)