Dynamical heterogeneities in glasses colloids and granular media Most of the solid materials we use in everyday life from plastics to cosmetic gels exist under a non crystalline amorphous form: they are glasses. Yet we are still seeking a fundamental explanation as to what glasses really are and to why they form. In this book we survey the most recent theoretical and experimental research dealing with glassy physics from molecular to colloidal glasses and granular media. Leading experts in this field present broad and original perspectives on one of the deepest mysteries of condensed matter physics with an emphasis on the key role played by heterogeneities in the dynamics of glassiness