There has been an increasing interest among clinicians in the quantitative assessment of the human locomotor function. The importance of this application in the orthopedic field is fundamental and requires further developments. Several studies have been published about gait analysis, many specific papers are available in literature, and a lot of conferences, symposiums and congresses have been dedicated to this matter. The quantity of information is enormous and sometimes it is not easy for the beginner to manage the different acquisition systems, acquisition methodologies and clinical interpretation of the resultant data. However, the consciousness of gait analysis s effective utility both in the research finding and in clinical decision making has made it indispensable in the present context. Our attempt, through this volume is to present an overview. Since we have worked up to now both in research and in clinical gait analysis, we have followed two major approaches in developing, on one hand the more appropriate methodology to obtain accurate and precise data, and on the other hand the best clinical results.