String theory has been developed to provide a complete theory of quantum gravity. After the discovery of the holographic principle and the AdS/CFT correspondence, there has been remarkable progress in this direction. Black holes in string theory have become marvelous physical objects for thought experiments and they have enabled us to microscopically verify string theory as a theory of quantum gravity. Recent studies on black hole information and holography reveal that quantum information theory plays also an important role in quantum gravity.

In addition to this original direction of research, holography in string theory has been proved to be an extremely useful tool to study strongly coupled field theories, and there are in particular many activities in the applications of holography to strongly coupled condensed matter systems.

Thus the "universe'' of string theory is now dramatically expanding by involving other fields of theoretical physics. The purpose of this workshop is to summarize these exciting recent developments and to raise important future problems. We hope this workshop will stimulate exchange of new ideas in various research directions.

This workshop will be held as a joint activity with Korea Institute for Advanced Study (KIAS) and Yukawa Institute for Theoretical Physics, Kyoto University (YITP). This is the 5th KIAS-YITP joint workshop and
you can find the links to the past KIAS-YITP workshops: 2005, 2007, 2009, 2011.

The present meeting is also a satellite workshop just after Strings 2013 which will be held in Sogang University, Seoul, Korea, during June 23-29, 2013.

This workshop is also supported in part by
the JSPS Grant-In-Aid for Scientific Research (A) No. 21244033 [Misao Sasaki] and
the JSPS Grant-In-Aid for Scientific Research (B) No. 25287058 [Tadashi Takayanagi].