IX
Preface
Human–computer interaction (HCI) is becoming ever more impor-
tant in interactive software. Such software has long been evaluated in
terms of the availability and breadth of its functions and its algorith-
mic efficiency. While such a developer’s perspective is still somewhat
valid, it has become difficult to differentiate among similar software
components from such an aspect given the amazing computing per-
formance of today’s hardware and the spread of algorithmic knowl-
edge and systems development know-how. us software quality is
increasingly judged from the users’ external point of view in terms of
their expectations, satisfaction, and experience. is external view
or user experience may be defined in many ways, but it is most obvi-