This book contains the extended lectures of the 8th Adriatic meeting which is traditionally devoted to the presentation of lectures on the most advanced scientific topics to young scientists, who actively participate, on an international level, in the development of their respective fields. The emphasis of the present meeting was on gauge theories, particle phenomenology, string theories and cosmology. The accompanying CD-ROM contains 27 additional contributions, of a length somewhat shorter than 25 presented in the printed book. .