Three works by Robert Jefferson Breckinridge (The Christian Pastor; Presbyterian Government, Not a Hierarcy, but a Commonwealth; and Presbyterian Ordination, Not a Charm, but an Act of Government) have been all but forgotten by modern Presbyterians. And yet, thanks to the reviewing work of James Henley Thornwell in the Southern Presbyterian Review, and the Biblical power of Breckinridge's ideas, much (though certainly not all) of what he believed has found its way into the Book of Church Order of the Presbyterian Church in America, and perhaps other American Presbyterian denominations (for instance, the right of rulings elders to lay hands on teaching elders being ordained and the need for ruling elders to make up a quorum of a church court are practices the PCA takes for granted, yet Breckinridge had to contend strenuously for them). Written in the middle of the debate over the nature and function of the ruling elder in the Old School Presbyterian Church in the 1840s (other authors who contributed to this debate include Thornwell, Thomas Smyth, and Charles Hodge), these works are worthy of your time. If you've never read these short treatises, you can find them here.