A golf ball, comprising: an inner core; an outer core, the outer core substantially surrounding the inner core; an inner cover layer, the inner cover layer substantially surrounding the outer core; and an outer cover layer, the outer cover layer substantially surrounding the inner cover layer; wherein the inner core has a first density value, the first density value being from about 0.85 g/cm 3 to about 1.1 g/cm 3; the outer core has a second density value, the second density value being from about 1.05 g/cm 3 to about 1.25 g/cm 3; the inner cover layer has a third density value, the third density value being from about 1.05 g/cm 3 to about 1.5 g/cm 3; the outer cover layer has a fourth density value, the fourth density value being from about 1 g/cm 3 to about 1.8 g/cm 3; wherein the inner core has a first Shore D hardness value, the outer core has a second Shore D hardness value, the inner cover layer has a third Shore D hardness value, the outer cover layer has a fourth Shore D hardness value; wherein the third Shore D hardness value is greater than each of the first Shore D hardness value, the second Shore D hardness value, and the fourth Shore D hardness value; the third Shore D hardness value is at least about 10 Shore D units greater than the fourth Shore D hardness value; and the golf ball has a moment of inertia of from about 82 g.cm 2 to about 90 g.cm 2 and; characterised in that: - the sum of the first density value and the second density value are at least about 2 g/cm 3; - the sum of the third density value and the fourth density value are at least about 2.2 g/cm 3; and - the sum of the third density value and the fourth density value are at least about 0.1 g/ cm 3 greater than the sum of the first density value and the second density value. an inner core; an outer core, the outer core substantially surrounding the inner core; an inner cover layer, the inner cover layer substantially surrounding the outer core; and an outer cover layer, the outer cover layer substantially surrounding the inner cover layer; wherein the inner core has a first density value, the first density value being from about 0.85 g/cm 3 to about 1.1 g/cm 3; the outer core has a second density value, the second density value being from about 1.05 g/cm 3 to about 1.25 g/cm 3; the inner cover layer has a third density value, the third density value being from about 1.05 g/cm 3 to about 1.5 g/cm 3; the outer cover layer has a fourth density value, the fourth density value being from about 1 g/cm 3 to about 1.8 g/cm 3; wherein the inner core has a first Shore D hardness value, the outer core has a second Shore D hardness value, the inner cover layer has a third Shore D hardness value, the outer cover layer has a fourth Shore D hardness value; wherein the third Shore D hardness value is greater than each of the first Shore D hardness value, the second Shore D hardness value, and the fourth Shore D hardness value; the third Shore D hardness value is at least about 10 Shore D units greater than the fourth Shore D hardness value; and the golf ball has a moment of inertia of from about 82 g.cm 2 to about 90 g.cm 2 and; - the sum of the first density value and the second density value are at least about 2 g/cm 3; - the sum of the third density value and the fourth density value are at least about 2.2 g/cm 3; and - the sum of the third density value and the fourth density value are at least about 0.1 g/ cm 3 greater than the sum of the first density value and the second density value.