Alexander Lubotzky, L\'aszl\'o Pyber, Aner Shalev: Discrete groups of slow subgroup growth In memory of S.A. Amitsur It is known that the subgroup growth of finitely generated linear groups is either polynomial or at least $n^{{\log n} \over {\log \log n}}$. In this paper we prove the existence of a finitely generated group whose subgroup growth is of type $n^{{\log n} \over {(\log \log n)^2}}$. This is the slowest non-polynomial subgroup growth obtained so far for finitely generated groups. The subgroup growth type $n^{\log n}$ is also realized. The proofs involve analysis of the subgroup structure of finite alternating groups and finite simple groups in general. For example, we show that there is an absolute constant $c$ such that, if $T$ is any finite simple group, then $T$ has at most $n^{c \log n}$ subgroups of index $n$.