The Brandeis Annotation Tool is a web-based text annotation tool that is centered around the notions of layered annotation and task decomposition. It allows annotations to refer to other annotations and to take a complicated task and split it into easier subtasks. The web-interface connects annotators to a central repository for all data and simplifies many of the housekeeping tasks while keeping requirements at a minimum (that is, users only need an internet connection and a well-behaved browser). BAT has been used mainly for temporal annotation, but can be considered a more general tool for several kinds of textual annotation.