The proteins from thermophilic organisms are the objects of the present study. Here it is specifically proposed a study on the microscopic origin of proteins thermostability using a multi-computational approach. The multi-methodological strategy is a powerful tool for exploring this issue since it allows an investigation at many different levels of molecular details. Neutron Scattering experiments will complement the in silico investigation.The present study will tackle the issue of thermostability under a new light by explicitly focusing on the role of hydration water and by carefully selecting homologues proteins from mesophilic, thermophilic and hyperthermophilic organisms as cases of study.I will investigate how the chemical composition of a protein surface, the distribution of charged, polar and hydrophobic amino acids, could be tuned in order to increase/reduce thermal resistance of the hydration layer and of the protein matrix. I will examine whether thermostability correlates to the flexibility or the rigidity of the protein matrix and/or of its hydration skin. I will study in details how the catalytic activity of enzymes is affected by the dynamics of the protein at extreme temperatures.The theoretical study will be supported by Neutron Scattering experiments gaining key knowledge on the structure and dynamics of hydration water and on the dynamics of proteins in the nanosecond time scale.Nowadays the possibility to design functional thermostable proteins is strategic for expanding the use of enzymes in industrial processes and in biotechnology. The study of the coupling between hydration water and protein surface could pave the way for the computer-aided engineering of thermostable proteins.