This paper analyses two approaches to the description of thermodynamic evolution. The first approach describes the dynamics of a thermodynamic system by contact vector fields extended with inputs and outputs while the second One interprets the. thermodynamic vector field as a smooth section of the tangent bundle of the respective Legendre manifold parametrized by n functions, called thermodynamic controls. It is shown that there is a duality between these two approaches similar to the one found in the symplectic case. However, there are still many open questions which present a waste opportunity for further research. 2016, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.