As long ago as 1867, I contributed to the Catena Classicorum a commentary on the Electra of Sophocles, followed in 1868 by one on the Ajax. At that time I already meditated a complete edition of Sophocles on a larger scale,– a design which I have never abandoned, though various causes have delayed its execution.

One of these causes may be briefly noticed here. In the course of preparing the commentaries on the Electra and the Ajax, I had been led to see more clearly the intimate relation which in certain respects exists between Greek tragic dialogue and Greek rhetorical prose, and to feel the desire of studying more closely the whole process by which Greek oratory had been developed. The result of this study was a treatise on the historical development of Attic prose style, which in 1876 was published under the title of The Attic Orators from Antiphon to Isaeos. The reception accorded to it has been most gratifying, and has more than repaid the labour which it had cost. It was, however, as a preparation, in one department, for the task of editing Sophocles that the special studies embodied in the Attic Orators had originally been undertaken: and, though they necessarily extended beyond that immediate scope, I do not regard the time bestowed on them as lost to the pur poses of the present work.