The workshop aims at gathering together experts in Spectral Theory, Spectral Geometry, Analysis of Partial Differential Operators, Homogenization and Asymptotic Analysis. The focus is on the interplay between the spectral properties of partial differential operators and the geometry of the underlying system. In particular the following topics will be discussed: spectral stability, shape optimization and extremum properties for eigenvalues, universal and asymptotic estimates for eigenvalues, upper and lower bounds, functional and isoperimetric inequalities, thin and perforated domains, boundary homogenization.