E-business has brought much change to our daily life and will become a necessary part of business, economy, and society. At least for the foreseeable future, e-business will keep growing. Each study of this dissertation was devoted to human-computer interaction (HCI) in e-business to improve website usability. First, data input tools were compared and optimal design characteristics were suggested for usable web based interaction. When proper input tools are employed, higher usability can be achieved. Second, a practical design process and the use of web elements were studied through the simulation of an e-bookstore. Web design influences e-business traffic and sales. Third, a grid menu was designed and examined for situations in which a menu contains a larger number of options. The grid menu was observed to be both robust and efficient. Fourth, an interaction model for the pull-down menu, including perceptive, cognitive, and motor behavior processes, was studied. The resulting model fit the experimental data well. Fifth, problems with iconic interfaces on e-business websites were reported and a methodology suggested to improve user interface design.