A current important find by the Derbyshire Record Office is a cookbook dating from 1742. The date makes it one of the oldest known comprehensive cookbook in Britain. It was previously thought that Mrs. Beeton's Book of Household Management from the mid 1800s was the oldest. This one beat it by a hundred years. Though the recipes in the former is confounding historians for the obscureness of its recipes and ingredients. For the full article head to BBC News.
P.S. There is an interesting discussion on the veracity of the above article in the comments section of this post. Please click and read on what Vanessa has to say.