An attachment system secures a residual limb to an artificial limb in a comfortable and substantially non-rotational manner. The attachment system offers proximal anchoring of the residual limb in a hard socket, by connecting a side surface of a residual limb liner to the side surface of the socket. Preferably, this connection is accomplished using an extension member extending from the liner through a portion of the socket interior, through the socket wall, and attaching to a latch mechanism. The preferred attachment system requires no clearance in the bottom of the socket well because neither the extension member nor the latch mechanism is located between the distal end of the residual limb/liner and the bottom of the well. The attachment system is preferably disposed entirely along the side of the limb and the side of the socket.