It is known that nuclear shells play a particularly important role in the collective motion of nuclear matter and, as a consequence, determine the structure of nuclei, nuclear dynamics, nuclear decay models, etc.In 1999 the nuclear shell model turned fifty, and the 49th meeting on Nuclear Spectroscopy and Nuclear Structure was devoted to nuclear shells in their various manifestations. The talks presented at the conference covered a wide range of experimental and theoretical studies.

Dramatic progress has been made in all branches of physics since the National Research Council's 1986 decadal survey of the field. The Physics in a New Era series explores these advances and looks ahead to future goals. The series includes assessments of the major subfields and reports on several smaller subfields, and preparation has begun on an overview volume on the unity of physics, its relationships to other fields, and its contributions to national needs. Nuclear Physics is the latest volume of the series. The book describes current activity in understanding nuclear structure and symmetries, the behavior of matter at extreme densities, the role of nuclear physics in astrophysics and cosmology, and the instrumentation and facilities used by the field. It makes recommendations on the resources needed for experimental and theoretical advances in the coming decade.