This book presents a self-contained introduction to H.M. Stark s remarkable conjectures about the leading term of the Taylor expansion of Artin s L-functions at s=0. These conjectures can be viewed as a vast generalization of Dirichlet s class number formula and Kronecker s limit formula. They provide an unexpected contribution to Hilbert s 12th problem on the generalization of class fields by the values of transcendental functions. This volume belongs on the shelf of every mathematics library."