Writers almost always, either consciously or unconsciously, make of their books mirrors of their personalities, eagerly exposing every trait to the public. But occasionally a writer wears a mask before this literary mirror and the public sees him only in disguise save perhaps in the pages of his intimate correspondence. Such a man was Hippolyte Taine, and it is a curious task to study this reserved scholar as he reveals himself in his books, to watch for the rare lines where he has dropped his mask in unguarded moments of secret ambition, of ennui or despair, of sudden mockery or mirth.