Understanding (as opposed to merely seeing) depends on being able to learn about the context of whatever is of interest and to know how it is related to its environment. For this reason, a library's collection of reference works provides an excellent environment for learning, but it is available only in one fixed place and during limited hours. So how can the same excellent environment be made available in a digital environment 24/7 anywhere from any personal computer?

The paper will provide a progress report on two related projects (one concerned with biographical texts <ecai.org/imls2006>, the other with Irish culture and heritage <ecai.org/neh2007>) concerned with the design and development of prototype interfaces that enable readers of digital texts to find explanations suitable for their interests and prior knowledge. Attention is being given to the special approaches needed for examining persons, places, and events.