This book presents a novel comprehensive thermodynamic framework, suitable for the design of new macroscopic models, as well as the combination of existing models. Our goal is to popularize thermodynamics for model designers. The example series of models includes very classic solid and fluid models, such as Newtonian, viscoplastic and viscoelastic materials, but also new heat effects and original combinations of existing models. The aim of the new proposed framework is to allow a clear and easy development of constitutive equations that automatically satisfy the second principle. Instead of writing directly constitutive relations, model designers are encouraged to first specify the energy. This book is primarily intended for graduate students and researchers in applied mathematics, engineering sciences, computational mechanics and physics. The reader is assumed to be familiar with classical mechanics, together with matrix and tensors algebra.