His letters lose their chief charm if the character of the man be not known, and the incidents of his life.
His essays on rhetoric--the written lessons which he has left on the art of oratory--are a running commentary on his own career as an orator.
Most of his speeches require for their understanding a knowledge of the circumstances of his life.

The treatises which we know as his Philosophy--works which have been most wrongly represented by being grouped under that name--can only be read with advantage by the light of his own experience.

There are two separate classes of his so-called Philosophy, in describing which the word philosophy, if it be used at all, must be made to bear two different senses.

He handles in one set of treatises, not, I think, with his happiest efforts, the teaching of the old Greek schools.

Such are the Tusculan Disquisitions, the Academics, and the De Finibus.