bringing together different strands of research (new and older) in Iwasawa theory and closely related topics by investigating class groups and Selmer groups in relation with characteristic power series and special values of L-functions, which have become classical topics in Iwasawa theory. The last few years have seen the emergence of some new trends such as non commutative Iwasawa theory, which studies certain p-adic representations attached to p-adic Lie groups, or equivariant theory, which provides an approach to the equivariant Tamagawa number conjecture, etc.