This paper describes research that seeks to facilitate the capture, representation, and reasoning about, temporal information by usability engineers. The product, a method we call KAT-LITTER, is an extension of Johnson and Johnson's (1991) Knowledge Analysis of Tasks (KAT). An evaluation of KAT-LITTER showed that it influenced the design process in two significant ways: firstly, designers using KAT-LITTER spent more time reasoning about temporal issues than designers using KAT alone, and secondly these same designers considered a broader spectrum of temporal issues. Further developments of KAT-LITTER are briefly discussed.