In connection with the class field theory a problem concerning p-groups was proposed by W. Magnus: Is there any infinite tower of p-groups G 1, G 2,…, Gn, Gn+1 ,…such that G1 is abelian and each Gn is isomorphic to Gn+1/θn(Gn+1), θn (G n+1) ≠ 1, n = 1,2,…, where θn (G n+1) denotes the n-th commutator subgroup of G n+1? The present note is, firstly, to construct indeed such a tower, to settle the problem, and also to refine an inequality for p-groups of P. Hall.