A coupler to be embedded in a first (e.g., flat) panel and an insert to be embedded in a second (e.g., flat) panel to be joined to the first panel during the assembly of an article, for example, of furniture. The coupler includes a coupler body, a cam bolt rotatable within the coupler body, a cam head carried by and rotatable with the cam bolt, and a lever extending from the cam bolt to a location outside the coupler body at which to receive a rotational pushing force. The insert has a hollow interior, a closed leading end extending laterally across the hollow interior, and a window formed in the closed leading end and communicating with the hollow interior. The cam head of the coupler is moved through the window in the closed leading end of the insert. A rotational force applied to the lever causes the cam bolt to rotate within the coupler body, which rotation is imparted to the cam head. The cam head is correspondingly rotated at the hollow interior of the insert so as to move out of alignment with the window in the closed leading end thereof to be relocated below the closed leading end. Accordingly, the coupler and the insert are connected in mating interlocking engagement with one another, whereby the first and second panels will be joined to one another without the use of tools or additional hardware fasteners.