Localized excitations in nonlinear complex systems : current state of the art and future perspectives ; [2nd Conference on Localized Excitations in Nonlinear Complex Systems (LENCOS 12)] The study of nonlinear localized excitations is a long standing challenge for research in basic and applied science as well as engineering due to their importance in understanding and predicting phenomena arising in nonlinear and complex systems but also due to their potential for the development and design of novel applications. This volume is a compilation of chapters representing the current state of the art on the field of localized excitations and their role in the dynamics of complex physical systems.