ICT Sustainability is about how to assess, and reduce, the carbon footprint and materials used with computers and telecommunications. These are the notes for an award winning on-line graduate course on strategies for reducing the environmental impact of computers and how to use the Internet to make business more energy efficient. These notes have been used for courses by the Australian Computer Society, Australian National University and Athabasca University (Canada). The book includes an extensive bibliography. Free open access course-ware is available on-line to accompany this text.