The Design of Everyday Things by Don Norman is one of my favourite books since it makes a number of design and interaction ideas easily accessible. His new book Living with Complexity is reviewed over at Core77. The underlying thesis is that what makes something simple or complex is whether the user understands the conceptual model. Unfortunately, to make our lives easier, people need progressively more complex and powerful tools. The key to making them useful is (1) meaningful communication and (2) compelling conceptual models. The review and the book are both worth reading. Learn more.