Einstein's theory of Gravity over hundred years now, is considered one of the most successful theories describing cosmic objects and their interactions. However, recent observations suggest that the Einstein's theory of Gravity may have to be modified. The aim of the 9th Aegean Summer School is to discuss recent developments on Gravity theory and its modifications, presenting scalar-tensor theories like generalized Galileon theories, Einstein-Cartan and Newton-Cartan theories, massive gravity and also Lorentz violating theories like the Horava-Lifshitz . Also, recent astrophysical and cosmological observational results will be discussed, and a status report on the BINGO, SKA and LIGO projects will be presented.

Invited speakers include: Elcio Abdalla, Ignatios Antoniadis, Eugeny Babichev, Eric Berkshoeff, Matteo Barsuglia, Christos Charmousis, Antonio  De Felice, Fawad Hassan, Lavinia Heisenberg, Kostas Kokkotas, Pablo Laguna,  Roy Maartens, Michele Maggiore, Paolo Pani, Kyriakos Papadodimas, Thomas Sotiriou, Ricardo Troconso, Shinji Tsujikawa.

The Aegean School is mainly addressed to postgraduate students and young researchers aiming at introducing them to these very challenging topics that recently have attracted much interest. Those graduate and postgraduate students interested in attending the school are requested to send a short CV and one recommendation letter to the School's Secretaries.

The 9th Aegean Summer School will take place in the island of Sifnos. The housing will be in the towns of Apollonia and Artemonas. The lectures will be given in the Sifnos Cultural Center "Μαριάνθη Σίμου" in Artemonas.

The 9^th Aegean Summer School is under the auspices of General Secretariat of Research and Technology and it is organized and sponsored by the National Technical University of Athens, Greece, the University of Groningen, Denmark, the University Paris-Sud, Orsay, France and PNCG France, the University of Nottingham, United Kingdom, the Pontificia Universidad Catolica de Valparaiso, Chile and the Instituto de Fisica, Universidade de Sao Paulo, Brazil, the Eugenides Foundation and Springer International Publishing.