Plato 
Sophist 

There are no descriptions of time, place or persons, in the Sophist and Statesman, but we are plunged at once into philosophical discussions; the poetical charm has disappeared, and those who have no taste for abstruse metaphysics will greatly prefer the earlier dialogues to the later ones. Plato is conscious of the change, and in the Statesman expressly accuses himself of a tediousness in the two dialogues, which he ascribes to his desire of developing the dialectical method.