NPR's Noah Adams travels to Chantilly, Va., for a conversation with Tom DeBaggio, his wife Joyce and son Francesco. Tom DeBaggio was diagnosed in the spring of 1999 with early-onset Alzheimer's disease. This is the fourth in a series of interviews with the DeBaggio family. In today's conversation, Tom describes his loss of familiarity with most of the material in his new book about the growing and the use of herbs, his willingness to give up driving when the time comes, and his acceptance of the need for an identification bracelet. He also tells of a harrowing experience one night when he accidentally took an overdose medication used in his Alzheimer's treatment. Book referenced is The Big Book of Herbs: a Comprehensive Illustrated Reference to Herbs of Flavor and Fragrance, by Arthur Tucker and Thomas DeBaggio Interweave Press, Loveland, Colo. ISBN 1-883010-86-1.