Due to current demographic trends and aging, more and more people are living alone and need proper support in their daily activities. An important aspect in overcoming the problems of people living independently is the use of Ambient Assisted Living (AAL) technologies. AAL is related to the use of ICT to increase the quality of life of elderly people and to prolong their independence. A number of research efforts deal with specific challenges of the field. In this paper, the emergence of AAL as a research field is described. Some research challenges are stated with special focus on user interaction, adaptation and customization aspects.