Separation of variables and superintegrability : the symmetry of solvable systems Separation of variables methods for solving partial differential equations are of immense theoretical and practical importance in mathematical physics. They are the most powerful tool known for obtaining explicit solutions of the partial differential equations of mathematical physics. The purpose of this book is to give an up to date presentation of the theory of separation of variables and its relation to superintegrability. Collating and presenting it in a unified updated and a more accessible manner the results scattered in the literature that the authors have prepared is an invaluable resource for mathematicians and mathematical physicists in particular as well as science engineering geological and biological researchers interested in explicit solutions.