The treatise is thrown into the form of a dialogue, which Cicero represents as his somewhat imperfect reminiscence of a conversation which had taken place at the Tusculan villa of L. Licinius Crassus, and had been reported to him by C. Aurelius Cotta, one of the interlocutors. That some such conversation did take place, we must of course believe; but it is scarcely credible that what Cicero gives us in these three books is anything but a fancy account of what he thinks ought to have been said, or what he would have liked to have been said, on the occasion. He calls it himself a non sane satis explicata memoria, a fairly vague expression which may perhaps be intended to imply that he will feel at perfect liberty to draw upon his own imagination, in order to supply the missing details of the conversation. However this may be, we have a long dialogue extending through three books, and it must he confessed that, as we read it, we are apt to forget in many places that it is a dialogue at all. No doubt at times there is a good deal of dramatic play, and a lively interchange of humorous and charming remarks; but the subject of conversation at such moments is not as a rule the question of oratory, but something extraneous to the main theme.