A classical theorem of Rényi [26] for the number of empty boxes, denoted by μ0(n,M), in a sequence of n random allocations of indistinguishable balls into M boxes with equal probability 1/M , can be stated as follows: If the variance of μ0(n,M) tends to infinity with n then μ0(n,M) is asymptotically normally distributed. This result, seldom stated in this form in the literature, was proved by R...