This is the second volume of the series entitled «Physics at the Turn of the Millennium.» This book contains five chapters. The first chapter is devoted to modern concepts pertaining to the nature of fundamental interactions. The second chapter describes some novel objects of atomic physics that attract an ever-increasing attention of researchers due to a variety of physical properties and phenomena inherent in these objects. These are the exotic and Rydberg atoms, excimers, clusters, fullerenes, endohedral compounds, and carbon nanotubes. The third chapter describes a major success in the understanding of the structure and dynamics of nuclear matter achieved during the last fifty years. In the fourth chapter, new nonlinear optical effects whose origin depends on light intensity are discussed. The interpretation of these effects is frequently related to microscopic laws of the interaction of light at molecular and atomic levels. The fifth chapter deals with quantum information, a new direction in physics deriving from some ideas of quantum mechanics that have been neglected until recently. The book is intended for everyone who is interested in the problems of modern physics.