The Gruffalo, by the same author and illustrator team, has to be one of the most famous picture books of recent years. It just avoided being the most famous picture book of this century, since it was published in 1999. I think it will almost inevitably become the The Very Hungry Caterpillar for this generation - our children will buy it for their grandchildren, and become nostalgic. Time was, Mr M and I could recite The Gruffalo without looking at the book. We possibly still could if forced to (although why either of us would ever be in that situation, I don't know!)
However Donaldson and Scheffler have collaborated on many other books. Our favourite when the kids were little was Monkey Puzzle, in which a monkey tries to find his mum.
I bought The Highway Rat because I absolutely love the poem "The Highwayman" and thought it might borrow from it. It does, a little, with the repitition, and it is a jolly enough tale. C enjoys the fact that the dastardly rat gets his comeuppance at the end, and he also likes the pictures of the cakes. What's not to love about pictures of cakes?