This book is a comprehensive overview of methods of characterizing the mechanical properties of engineering materials using specimen sizes in the micro-scale regime (0.3-5.0 mm). A range of issues associated with miniature specimen testing like correlation methodologies for data transferability between different specimen sizes, use of numerical simulation/analysis for data inversion, application to actual structures using scooped out samples or by in-situ testing, and more importantly developing a common code of practice are discussed and presented in a concise manner.