Boolean2Objects is a new command in V4 that allows you to select two objects and cycle through the four possible outcomes of a Boolean operation (with preview) - Union (fusing the two together) Subtract A from B, Subtract B from A, and Intersection (leaving only the overlapping volume of A and B). This is especially helpful if you have open objects, as it is not necessary to look at surface directions, one of the four possibilities will always be what you want.