This book is an introductory text for all earth scientists interested in learning about the quantitative description of geological problems. It contains chapters on heat flow, sedimentary basin modelling, mechanics of continental deformation, PT path modelling, geomorphology and mass transfer and more. In its style, the book is aimed at the field oriented geologist that wants to begin with learning about the quantitative description of problems. Graduate students and scientists will find the book a good starting point for a quantitativ treatment of their data.