On the trail of the breads of yore, today a friend of mine passed on a recipe for hardtack which appeared, of all places, on Boing Boing. Hardtack is simple to prepare: here's the recipe in toto:
Mix 2 cups all-purpose flour, 2 cups whole wheat flour, and 1 tsp salt. Form it into a dough using 1.5 cups of water.
Let the dough rest for 10 minutes. Then spread it into a pan, prick it all over on top with a fork, and bake it for 50 minutes at 325 degrees F.
I'm not terribly interested in trying hardtack, which, aside from the texture that earned it its name, has a reputation for becoming wormy. However, according to Boing Boing, this particular recipe comes from a cookbook called The Food Journal of Lewis & Clark: Recipes for an Expedition by Mary Gunderson; Boing Boing claims that the other recipes in that book--which presumably are of late 18th - early 19th century provenance--are much tastier. Now I'm curious about the other recipes in that book; I think I will have to track it down. If I do, I'll write about it.
EDIT: A friend of mine wrote a short article about hardtack noting that it becomes wormy only if it is not absolutely shielded from dampness. It also discusses similar bread products made to have a long shelf life, such as pilot bread. The article may be found here.