The lectures presented a variety of new developments in heavy ion reaction theory of the different energy domains ranging from low energy to intermediate energy and high energy.

This volume contains the invited contributions that were presented at the Predeal International Summer School in Nuclear Physics 2006. It covers the recent achievements in the fields of nuclear structure, double beta decay, nuclear multifragmentation, kaon and dilepton production in heavy ion collisions, and the quark-gluon plasma. The treatment is both theoretical and experimental, with emphasis on the collective aspects and related phase transitions. The papers are authored by many leading researchers in the field.

The Predeal International Summer School, held at the Institute for Physics and Nuclear Engineering, Bucharest, Romania, is a prestigious scientific event. The school first took place in 1969 and since then it has been held every two years.This year the lectures were given by more than 30 outstanding professors, covering timely subjects in theoretical and experimental nuclear physics. In addition, there were special sessions of contributed papers presenting the most recent results in these domains. The aim of the school was thus two-fold: to give basic information on some hot subjects of research in nuclear physics and to present them with the most recent achievements in these fields. This volume contains the proceedings of the school.