Ever since the development of thin film patterning techniques ferromag- nets have offered the potential for fast, high density and non-volatile in- formation storage. In the last decade new ways to couple magnetic and electrical systems have been identified. These developments have unlocked the potential of nanomagnetic systems and they will play a significant role in surmounting Silicon's scaling limitations. Central to the development of these novel devices will be quantitative methods. This book considers one such method, Magnetic Force Microscopy (MFM), an operating mode of the ubiquitous atomic force microscope. A theoretical and experimental analysis of image formation in MFM is presented and a fast approximate numerical model for MFM is outlined. This model forms a basis for tackling the two principal challenges encountered when using MFM: image interpretation and quantitative measurement.