The Character of God by David Pawson - Book - is currently on backorder. You may still purchase now though and we'll ship as soon as more become available.
While the author was preparing a series of sermons on God's multifaceted character, he hit on the idea of linking divine attributes to the letters of the alphabet, hoping thereby to make it easier for his listeners to remember them. All went well until the letter 'X'. Whether this was dealt with satisfactorily the reader is left to decide.