"[W]e have only the work as evidence for the only kind of sincerity that concerns us: Is the implied author in harmony with himself--that is, are his other choices in harmony with his explicit narrative character?... A great work establishes the "sincerity" of its implied author, regardless of how grossly the man who created that author may belie in his other forms of conduct the values embodied in his work. For all we know, the only sincere moments of his life may have been lived as he wrote his novel." (75)
Booth brings in the implied reader too. I.e., the critical conversation is getting crowded. Real author, implied author, narrator/persona, characters, implied reader, real reader. But he shows that there are real links between the implied reader and real reader--talking about how because of who he is, he is not able to become the implied reader that Lawrence's implied author asks for. (Cites Gibson's "mock reader" as another term.) I.e., the implied reader I become is not me, yet there are limits to the implied readers I can become. (137-39)
"I now see that for some purpose I must make problematic the sharp distinctions I once made between flesh-and-blood authors and implied authors and between the various readers we become as we read and the actual breathing selves we are within our shifting cultures." (415). And goes on to cite pages in Critical Understanding where he takes that up (esp. 272-318). (Booth, Wayne. The Rhetoric of Fiction. Chicago UP, 2nd ed. 1983).