ActivExpression, from Promethean, is much more than a clicker or voting system. Its functions allow learners to text ideas to an Activboard or Smart Board, to express opinions, to answer questions at their own pace, and it allows teachers to run quizzes or tests with instant electronic analysis, to send feedback live to individuals' handsets congratulating them or advising them of mistakes (with explanations), and to differentiate effectively by asking learners to start at different points in a test. Learners are highly motivated by the technology and they love the live feedback function. One learner said of this 'It's like having a teacher sat on your shoulder'. This chapter shows users all the functions and how to make best use of the technology. This is a users' manual for teachers new to ActivExpression or for Principals or Superintendents keen to know how to improve learning, assessment and behavior through the use of technology.