Jimmie Lawson Directed Complete Completions Abstract: We introduce a variant of the Scott topology, called the D-topology. We consider the D-completion for both topological spaces and posets and derive its basic properties. For partially ordered sets the D-completion turns out to be a natural dcpo-completion that generalizes the rounded ideal completion. We establish that various types of continuous operations extend uniquely continuously to the D-completion, and thus this completion provides a potentially useful approach to dcpo-algebras.