Life-like characters is one of the most exciting technologies for human-computer interface applications today. They convincingly take the roles of virtual presenters, synthetic actors and sales personas, teammates and tutors. A common characteristic underlying their life-likeness or believability as virtual conversational partners is computational models that provide them with affective functions such as synthetic emotions and personalities and implement human interactive behavior. The wide dissemination of life-like characters in multimedia systems, however, will greatly depend on the availability of control languages and tools that facilitate scripting of intelligent conversational behaviour. This book presents the first comprehensive collection of the latest developments in scripting and representation languages for life-like characters, rounded off with an in-depth comparison and synopsis of the major approaches. Introducing toolkits for authoring animated characters further supports the ease of use of this new interface technology. Life-like characters being a vibrant research area, various applications have been designed and implemented. This book offers coverage of the most successful and promising applications, ranging from product presentation and student training to knowledge integration and interactive gaming. It also discusses the key challenges in the area and provides design guidelines for employing life-like characters.