A collaborative system is a real-time computer-based environment for cooperative work. Computer systems have been available for some time to assist individuals with their work, but the use of computers by groups is underdeveloped. The thesis of this dissertation is that a collaborative system can be built in a principled way using network-connected workstations and that such a system can enhance group work.

Previous systems to support group work have generally either avoided computers, as in teleconferencing, or have relied on long-haul networks to support asynchronous message-passing, as in computer conferencing.

This dissertation focuses on real-time software tools to support groups working together in the same room. The Colab system and its tools explore the following properties of computer-based cooperation: the structure of the problem-solving process, the design of multi-user interfaces, social coordination, simultaneous activity, maintenance of consistent views of shared objects, and uses for digitally captured meetings.

To better understand and evaluate computer-based collaborative tools and their uses, the Colab system and the Cognoter presentation tool were implemented and used for both real and posed idea organization tasks. To test the system design and its effect on structured problem-solving, many early Colab/Cognoter meetings were monitored and a series of preliminary experiments were performed. These early observations indicated that people can and do work more efficiently and in parallel if they are given tools that help them stay focused and that help manage the added complexity of multi-user interactions.