This book covers the major physical and mechanical processes that unfold during cementing and subsequent well service, and which can affect the well integrity. Focusing on the underlying physics, it concisely presents the central concepts of well cementing. The authors discuss the displacement of different fluids in the annulus, the mechanical stability of cement subject to varying downhole temperature, pressure and in-situ stresses, and the impact of defects on cement integrity under different mechanical and thermal loads over the course of the well's lifetime. The book identifies knowledge gaps and unresolved issues, and proposes new directions for future research and development. The book is a valuable resource for practising engineers in the oil and gas industry, academic and industrial researchers involved in oil and gas engineering, and to graduate students within this same sector.