In this talk, I will discuss the effects of protein denaturants(such as urea) and protectants (such as TMAO) on liquid water structure and dynamics, on hydrophobic hydration, and on polypeptide aqueous structure. I will focus on the discussion of direct and indirect effects of cosolvent in solvaton. I will also present recent studies on the possible long range effect of hydrophobic effects on liquid water structure and on solvation of both electrolytes and small organic molecules.