The Timber Framers Guild of North America chronicles the experience of the 50 timber framers who journeyed to Loch Ness in Scotland with the NOVA team of experts to reconstruct a medieval trebuchet. The group, whose members built the trebuchets used in the NOVA documentary, "Secrets of Lost Empires: Medieval Siege," have provided a running log of the trip and also include numerous snapshots.

Offered by Castles Unlimited, an education and preservation group, this site has numerous features, including information about the many castles scattered throughout Britain. Of particular note is the "Castle Learning Center" that includes essays on castle topics ranging from water defenses to knighthood.

This 200,000-word online book has numerous essays and beautiful illustrations. Medieval society, culture, and warfare are all discussed in depth.

The Grey Company is a historical re-enactment group based in Perth, Australia. This page provides you with everything you would want to know about trebuchets, including pictures of medieval trebuchets, mathematical models for the weapon, and plans for table-top models that you can build. The group's Web site also contains information about medieval warfare and costume-making for re-enactments and includes an extensive list of relevant links.

This site was produced by Chronique: The Journal of Chivalry, which advertises itself as "the only print journal of students, re-enactors, tournament companies, teachers, and anyone interested in the philosophy and history of chivalry, fighting techniques, or how-to articles." Check out its glossary, which includes hundreds of medieval words such as dais, dubbing, and demesne.

The National Engineers Week Committee unveils plans for its 49th meeting which include numerous activities to showcase new projects and programs intended to spread the message of engineering's importance to society. The site also provides adolescents with an opprtunity to investigate a host of engineering achievements designed to inspire their interest in engineering.

This book provides extensive information about the weapons used during a siege and their evolution throughout medieval times.

A colorful large-format book that serves as a wonderful introduction to everyday life inside a castle, covering entertainment, food, work, and more.

Award-winning illustrator David Macaulay creates a fictional castle inhabited by Lord Kevin in the imaginary town of Aberwyvern. Macaulay tells a story about how castles were built, who lived in them, and how they were defended. The book is full of wonderful line drawings and details about castle life.

This colorful young adult book, part of a series of examinations of different periods and places in history, is a wonderful introduction to everyday castle life. It has intricate drawings of castles - including a castle siege - that draw the reader into medieval life.

This illustrated book goes into detail about knights' armor, weapons, war-horses, castles, heraldry, and hunting.

Kids ages 9-12 and their families can explore the once-mighty civilizations featured in the Secrets of Lost Empires series with this fully illustrated, 32-page book. Just $4.95 to cover shipping and handling. Call 1-800-949-8670 or write to: WGBH Boston Video, P.O. Box 2284, South Burlington, VT 05407-2284.