Ion mobility spectrometry (IMS) is an analytical technique used to separate and identify ionized molecules in the gas phase based on their mobility in a carrier buffer gas. Though heavily employed for military or security purposes, such as detecting drugs and explosives, the technique also has many laboratory analytical applications, including the analysis of both small and large biomolecules. IMS instruments are extremely sensitive stand-alone devices, but are often coupled with mass spectrometry, gas chromatography or high-performance liquid chromatography in order to achieve a multi-dimensional separation. They come in various sizes, ranging from a few millimeters to several meters depending on the specific application, and are capable of operating under a broad range of conditions. In the present book, ten typical literatures about ion mobility spectrometry published on international authoritative journals were selected to introduce the worldwide newest progress, which contains reviews or original researches on ion mobility spectrometry. We hope this book can demonstrate advances in ion mobility spectrometry as well as give references to the researchers, students and other related people.