The Second International Symposium on Physics of Photons (ISPP 15) will be held on July 3-5, 2015 (Friday - Sunday) at the Institute of Modern Physics (Chinese Academy of Sciences) in Lanzhou, China. Such a conference is continuation of the previous International Symposium on Physics of Photons (ISPP 13, September 27-29, 2013) at the Institute of Modern Physics (CAS, Lanzhou, China). Homepage of this conference is http://photon2013.csp.escience.cn. ISPP 15 will be dedicated to all aspects of physics of photons in different types of reactions inside the energy region from the lowest up to high. In particular, the conference will be focused to photons as sensitive tools for study of properties of nuclear and quark matters. At the meeting recent progress in our understanding of photons in nuclear and particle processes will be presented. The Symposium will cover such questions studied by means of photons as strong and electroweak interactions, structure, many-nucleons effects, non-stationary picture and dynamics of studied reactions, dissipative effects, quantum non-locality effects, vacuum polarization and light-by-light scattering, photon collider prospects, new acceleration techniques and future accelerators topics, etc. In addition, recent results on physics of photons in tasks of astrophysics, black holes, cosmology and other related topics will be discussed. In theory we plan to analyze current progress in modern theoretical models, vital problems in physics and open unresolved questions, establish perspectives for further investigations. We put special attention to experimental study of photons where we should like to summarize existed progress, to indicate vital problems and understand their reasons, to see ways for possible resolutions, and to establish the most important further directions. The purpose of this meeting is to review the principal developments that have occurred in resent years, to present the main results leading to current work in subject in a coherent form that will be accessible to graduate students and young researchers newly entering the domain, and to point out the most promising directions for future research.