title: Classical and non-classical tools for minimal surfaces. 4 lectures at the "Fifth Summer School in Analysis and Applied Mathematics". Universitˆ La Sapienza, Roma, June 1-5, 2009. abstract: In the first part of this series of lectures I will recall the basic notions from classical Complex Analysis, Differential Geometry and Calculus of Variations which are used in studying minimal surfaces and area-minimizing problems, both in the parametric and intrinsic approach (area formula, conformal maps in the plane, Riemann mapping theorem, mean curvature and Gauss curvature of a surface, first variation of the area). This should cover in particular most of the background material needed for the lectures delivered in parallel by Stefan Hildebrandt. The last two lectures contain an introduction to the theory of Finite Perimeter Sets, including the main results of the theory (compactness, structure of distributional derivative, rectifiability) and a brief outline of few applications, namely existence results for minimal surfaces and capillarity problems.