Dr. Michael Haykin has compiled a number of Edward's letters in a new series from Reformation Heritage Books. The new series is called Profiles in Reformed Spirituality.
I read the whole book on the plane on the way to the Banner of Truth Conference and could not put it down! The book begins with a short biography of Edwards that discusses the depth of his spirituality. He dethrones some of the popular myths about Edwards and shows him as a deeply committed man of God.
He then moves into the letters and further develops Edwards as a man who was committed to practical theology and the glory of God. The footnotes by Haykin help the reader through the letters in a way that lends understanding to the sociological and religious milieu of the day. These footnotes should be expanded for lay readers into the whole corpus of Edwards' letters (hint, hint Dr. Haykin).
If you have not read Edwards this is a helpful place to begin. It is warm, experiential, and quite practical. The piety of Edwards should be a boon to those of us who are unsatisfied with the low levels of commitment to spiritual things in the current Reformed world.
I look forward to the second book in this series, which according to rumor is, on John Owen and will be penned by Dr. Sinclair Ferguson.