Over the last 5 years, we have successfully applied differential scanning calorimetry (DSC) to study silicon thin films. The aim of this paper is to review our main results to give an overview of the possibilities offered by this technique, which is widely used to characterize solid state transformations. We will address some classical subjects related to the structure of pure and hydrogenated a-Si, such as the strength of the Si-H bond, hydrogen diffusion and the contribution of structural defects and strained bonds to the enthalpy of structural relaxation and crystallization. Special attention will be paid to the crystallization kinetics of films with structures ranging from pure amorphous to highly crystalline. Despite previous expectations, in films deposited at low temperature, the presence of nanocrystals embedded in the amorphous phase does not promote crystallization. In fact, the crystallization temperature is much higher than expected from a simple solid state epitaxy mechanism, which indicates low coupling between the amorphous and crystalline phases. (C) 2009 Elsevier B.V. All rights reserved.