John Maynard Keynes said of it: "In my opinion it is a grand book ... Morally and philosophically I find myself in agreement with virtually the whole of it: and not only in agreement with it, but in deeply moved agreement." However, Keynes did not think Hayek's philosophy was of "practical" use; this was explained later in the same letter, commenting: "What we need therefore, in my opinion, is not a change in our economic programmes, which would only lead in practice to disillusion with the results of your philosophy; but perhaps even the contrary, namely, an enlargement of them. Your greatest danger ahead is the probable practical failure of the application of your philosophy in the United States."