This volume contains papers contributed to the Second Symposium on Hybrid RANS-LES Methods, held in Corfu, Greece, 17-18 June 2007. All the papers have undergone further review and revision after the symposium, which has covered a number of relevant topics in the field. These include Unsteady RANS and LES, Improved DES Methods, Hybrid RANS-LES Methods, Embedded LES, DES-related Numerical Issues, Performance of the New SAS Model, as well as Industrial Applications of DES. Papers represent a leading part of current studies and achievements on the fundamentals of hybrid RANS-LES methods in general, as well as on their applications to industrial flow problems. Among the contributed papers, three invited keynote papers by B. Geurts, U. Piomelli and P. Sagaut, are presented together with an overview paper by P. Spalart.