The aim of this book is to provide the researcher with important sample preparation strategies in a wide variety of analyte molecules, specimens, methods, and biological applications requiring mass spectrometric analysis as a detection end-point. In this volume we have compiled the contributions from several laboratories which are employing mass spectrometry for biological analysis. With the latest inventions and introduction of highly sophisticated mass spectrometry equipment sample preparation becomes an extremely important bottleneck of biomedical analysis. We have a goal of giving the reader several successful examples of sample preparation, development and optimization, leading to the success in analytical steps and proper conclusions made at the end of the day. This book is structured as a compilation of contributed chapters ranging from protocols to research articles and reviews. The main philosophy of this volume is that sample preparation methods have to be optimized and validated for every project, for every sample type and for every downstream analytical technique.