Doolittle's Treatise Concerning the Lord's Supper is a typically masterful work by a spiritual doctor. He not only examines our hearts for preparation for the Supper, but also what we will gain spiritually through communion with Christ, and what will hinder that communion.
He also has three "Dialogues" in which he addresses the needs of every kind of participant, those burdened with sin and those passionate to meet the Lord at the Table.
Of particular concern to the Puritan pastor were those who were reluctant to go to Communion, and he answers their objections with both grace and plain speaking.