Aeschylus: Eumenides by Anthony Podlecki

Published by Aris and Phillips in 1989, a commentary of the play keyed to Greek text with facing English translation. This is especially useful for beginners.

Aeschylus: Eumenides by Alan H. Sommerstein

Published by Cambridge University Press in 1989, an extensive introduction, commentary, and Greek text of the play especially suited to more advanced readers of Aeschylus.

Aeschylus: Eumenides by Robin Mitchell-Boyask

A helpful overview of the play and its cultural and literary context published by Duckworth in 2009 (part of the Companions to Greek and Roman Tragedy series).