Internality and interpretable automorphism groups in simple theories

The binding group (which we call the automorphism group) theorem for stable theories is partially extended to the simple context. Some results concerning internality are proved. We also introduce a 'small' normal subgroup G₀⁺ of the automorphism group G = Aut(p/Q) and show that if p is Q-internal then it has a finite exponent and G/G₀⁺ is interpretable.