David Macaulay builds a castle in front of you, stone by stone, and explains every decision as if you were standing on the scaffolding next to him. Text and extraordinarily detailed pen and ink drawings follow the planning and construction of a castle and its adjoining town in thirteenth century Wales, from the surveyor's first stakes in the ground to the finished walls under siege.

The drawings are the kind you fall into. Cutaways open the towers to show how a spiral stair actually winds, how a portcullis drops, why the walls are thick where they are thick. It reads as a story, works as an engineering course, and rewards the tenth viewing as much as the first, which is why adults keep borrowing it back from children.

A Caldecott Honor book, 80 pages in a large 9 by 12 inch format that gives the drawings the room they deserve. For every reader who has ever looked at a castle and asked how.