The Andromeda Galaxy is in notable interaction with its companion M32, which is apparently responsible for a considerable amount of disturbance in the spiral structure of M31. The arms of neutral hydrogen are displaced from those consisted of stars by 4000 light years, and cannot be continuously followed in the area closest to its smaller neighbor. Computer simulations have shown that the disturbances can be modelled by a recent close encounter with a small companion of the mass of M32. Very probably, M32 has also suffered from this encounter by losing many stars which are now spread in Andromeda's halo.