What is the theme in Whittington by Alan Armstrong?

Courage overcomes difficulties is arguably the book's primary theme, manifesting as it does in several ways in each of the work's main narrative lines, or plots. First there is the Whittington plot, in which Whittington the cat comes to live in the barn and develops friendships there. The value of courage in overcoming difficulties is evident right from the first moments of this plot, in which Whittington, who has difficulty walking, convinces the other members of the barn family, who have difficulty with the idea of welcoming another predator into their little community, to let him move into their home. Whittington's problems with walking are themselves overcome when he courageously helps The Lady fight off the repeated attacks of Havey the dog.