On Lying - Saint Augustine of Hippo

I have also written a Book on Lying, which though it takes some pains to understand, contains much that is useful for the exercise of the mind, and more that is profitable to morals, in inculcating the love of speaking the truth. This also I was minded to remove from my works, because it seemed to me obscure, and intricate, and altogether troublesome, for which reason I had not sent it abroad. - Summary by Augustine