A "BIG-BELLIED Lutheran God" within the young Updike looked on in contempt as he struggled to give up cigarettes. Many years later the older Updike, now giving up on alcohol, coffee and salt, put into the mouth of that God the words of Frederick the Great excoriating his battle-shy soldiers -- "Dogs, would you live forever?" But all the life-enhancing substances were set aside, and writing became Updike's "sole remaining vice. It is an addiction, an illusory release, a presumptuous taming of reality." In the mornings, he could write "breezily" of what he could not contemplate in the dark without...