The School “Neutrino Physics and Astrophysics”, held in Varenna (Villa Monastero), from July 26 to August 5, 2011 was a joint event of the International School of Physcics “Enrico Fermi” of the Italian Physical Society (SIF), and of the network International School of AstroParticle Physics (ISAPP).

The “Enrico Fermi” School is a prestigious SIF institution located in VarennaVilla Monastero. It has been active since 1953 and hosts, as teachers, the most distinguished scientists coming from all over the world. The School organizes three-to-four events per year, covering all areas of physics, including physics-based interdisciplinary topics.

The International School of Astro-particle Physics (ISAPP) is a network, born in 2002, whose aim is the build-up of an actual astro-particle community, merging astrophysicists and particle physicists. The organization of Schools and Summer Institutes is one of the activities of the network, which is a net of 33 Institutes in Europe, Russia and Israel.

The ISAPP Schools are true didactic schools at the level of PhD students. The lectures are planned to give both the basic elements and the more recent developments of the central topics of the School. Extended discussions among students and teachers take place in the lecturing hall during the school and at the lunches and dinners, jointly attended by all the participants. In addition, outlines concerning the Standard Model of Elementary Particles and the Cosmology are always given as introductory lectures, to help both the Elementary Particle and Astrophysics communities to reach a common background.

These Proceedings are the written version of the lectures presented at the School and in some cases expanded and upgraded. They do not include the pre-school lectures, which would need a very extended and long text, and a few lectures because they were not translated in a written version by the lecturers (F. Gatti, M. Thomson, C. Peñna-Garay).

The Proceedings contain at the end short communications about the physics results presented in the form of posters by the students during the School. About ten of them have been selected also for an oral presentation.

We hope that this Volume will be useful not only to the participants of the School, but also to other PhD students and young physicists.

We acknowledge the very important support of the Italian Physical Society and the important help of the “Camera di Commercio” of Lecco, the Italian National Institute for Nuclear Research (INFN), the Italian National Institute of Astrophysics (INAF) and the Physics Department of the University of Milan (UNIMI).

G. Bellini and L. Ludhova