Topics on Analysis in Metric SpacesThis book presents the main mathematical prerequisites for analysis in metric spaces. It covers abstract measure theory, Hausdorff measures, Lipschitz functions, covering theorums, lower semicontinuity of the one dimensional Hausdorff measure, Sobolev spaces of maps between metric spaces, and Gromov Hausdorff theory, all developed ina general metric setting. The existence of geodesics (and more generally of minimal Steiner connections) is discussed on