Currently, the knowledge of immunological memory is quite broad. On the one hand, advances in exploring particular mechanisms involved in immunological memory process have provided answers to many fundamental questions. On the other hand, they also contributed to posing new important ones. Our knowledge about precise mechanisms of generation, maintenance and properties of memory T cells remains limited. Crucial aspects in the understanding of immunological memory include information about memory cell properties as well as endeavor to consider the immunological memory process as a function of the immune response as a whole.