Abstract: The present invention provides a disconnect which has the internal integrity to make it as strong as the rest of the drill string. The present invention can disconnect when desired, despite the fact that the apparatus is at that time subjected to significant tensile or compressive loads. The invention allows for disconnection by alternative methods. Accordingly, in one version of the tool, a ball can be dropped or pumped to a seat to facilitate disconnection. In another version of the tool, that may employ an internal wireline precluding the use of a ball, disconnection can be accomplished by compression of a stack of Bellville washers, in response to a tensile force, to release a collet-locking mechanism. Either design features a rotational locking component.