This book provides information on characterizing the microstructure and mechanical properties of cementitious materials at microscale. Specifically, with the intention to  provide the methods of preparing the samples for the micro-scale mechanical testing, to address the techniques for measuring and analyzing the elastic modulus, the stiffness, and the fracture toughness of cementitious materials at micro scale by instrumented indentation, to describe a method for measuring and interpreting creep behavior of cementitious materials at micro scale, and to demonstrate the homogenization method for obtaining the mechanical properties of cementitious materials across scales. The information in this book is helpful to a wide readership in the field of civil engineering and materials science working with cementitious materials and other composite materials.