Lincoln the father -- and some of the adventures and misadventures of his youngest son, Tad, whose greatest ambition was to own a goat, and who was continually foiled in this by his mother. Anecdotal material which has legendary value, though some of it is flavored agreeably with a fictional quality. (Did the goats help uncover the mystery of the lost plans?) The ""green umbrella"" was symbolic of the need of sheltering Mrs. Lincoln' against the buffets of fate.