A coupler for joining a pipe to another pipe, a tee, or other fitting, and more particularly, to a coupler which provides positive retention of the gasket about the circumference of the coupler sufficiently to precisely position and hold the gasket during placement about pipe ends and / or fittings to be coupled, and which provides controlled circumferential compression of the gasket during coupling, for positive sealing when the coupler is closed, while allowing one handed handling and operation during placement and coupling, such that the other hand can be used for supporting a pipe to be coupled, and which is operable for releasing and breaking loose the coupler and associated gasket from a pipe during uncoupling.