As Tolkien got older, he increasingly denied the participation of others in the creation of his work. Tolkien says this is one of the few places where Lewis's detailed criticisms were useful and just. It may be more accurate to say this is one of the few places where Tolkien specifically acknowledges the careful editing of his friend. Changes
Tolkien, as he aged, grew more insistent that his literary creations were solely his own, often downplaying the contributions of others in his process. This shift indicates a desire to emphasize the individuality of his work, despite the collaborative environment he was part of, particularly with peers like C.S. Lewis.
The book "Bandersnatch" by Diana Pavlac Glyer mentions that Tolkien recognized Lewis’s detailed critiques as not only valuable but also just in some instances. This suggests a nuanced acknowledgment of Lewis's role in refining Tolkien's ideas, highlighting that social discourse was critical in the development of Tolkien's literature.