Ultrasonic phased array testing is a powerful NDT technology and one whose use is growing rapidly, however it can seem complex to a person who has not worked with it. This self-guided tutorial is a basic introduction to ultrasonic phased array testing, both for newcomers and for more experienced users who want a review of basic principles. It begins with what phased array testing is and how it works, then outlines some considerations for selecting probes and instruments, and ends with links to phased array application notes and a phased array glossary. In addition to text and illustrations it includes a series of interactive Flash files as learning tools.