Upper bounds for |L(1,chi)|

Given a non-principal Dirichlet character chi mod q, an important problem in number theory is to obtain good estimates for the size of L(1,chi). In this paper we focus on sharpening the upper bounds known for |L(1,chi)|; in particular, we wish to determine constants c (as small as possible) for which the bound |L(1,chi)| <= (c+o(1)) log q holds.