Inverse heat transfer method (IHTM) is typically used for predicting the temperature, heat flux, and other physical properties of a thermal system. In recent years, it has been applied to treat the problems of shape identification, shape design, and identification of geometric and physical variables simultaneously. In this volume, the conjugate gradient method (CGM) is extended and applied, while a simplified variation of CGM that overcomes the limitations in the definition of objective function form of CGM is presented. Combining these developments, a novel IHTM is proposed, which incorporates an automatic-filter scheme with the CGM method, and is applied to a wide range of practical problems for thermal systems. Since numerical grid generation is not required and overwhelming mathematical manipulations are avoided, the objective function form presented here becomes very flexible. The content of this volume is most suitable for readers interested in IHTM and its wide applications, and hopefully will also stimulate novel thoughts of the readers to help them develop and apply to their own innovative problems.