The 23 articles in this volume encompass the proceedings of the International Conference on Modules and Comodules held in Porto (Portugal) in 2006.

The conference was dedicated to Robert Wisbauer on the occasion of his 65th birthday.

These articles reflect Professor Wisbauer's wide interests and give an overview of different fields related to module theory.

While some of these fields have a long tradition, others represented here have emerged in recent years.

The submissions include topics in the formal theory of modules bordering on category theory, in ring theory, in Hopf algebras and quantum groups, and in corings and comodules.

Postgraduates and researchers in module and ring theory and related areas like Hopf algebras and the theory of comodules and corings