The 6th International Conference on PErvasive Technologies Related to Assistive Environments is organized by the University of Texas at Arlington, USA. The PETRA Conference brings together different types of technology to address an important social and healthcare issue: as the world's population ages, there is growing interest in solutions for the in- home care of the elderly as well as for the care of people with Alzheimer's, Parkinson's and other disabilities or traumas. PETRA (which means "stone" in Greek) reflects the needs of the domestic environment, or "Oikos" as it was known in ancient Greece, but from a technological perspective. People's living environments are particularly important in an increasingly crowded and complex world where the need for inclusiveness and connectivity with the rest of the world is key. PETRA addresses the fact that, as people grow older, they will increasingly rely on technology to be able to stay in their homes.