The purpose of this paper is to explain why it is fruitful to think of Wiener space as an infinite--dimensional sphere of radius $\infty\frac{1}{2}$. The idea goes back to Levy and Wiener and has recently been employed to advantage by Hida; Hida, Kubo, Nomoto and Yosizawa; Kono; Orihara and Umemura; their results will be reported upon below.