A golf ball has a cover and a core which is made as a single piece or of two or more parts (for example an inner core covered by an outer core or mantle layer). The ball has non-spherical aspects in at least some parts and may also have different specific gravities in different parts of the ball. The different shaped ball parts combined with the different specific gravities of the materials for different ball parts results in a differential between the moments of inertia of the different spin axes. The golf ball is spherical, but the inner layers are not necessarily completely spherical or symmetrical layers or parts.