Abstract: It was previously shown that at critical central charge, N-extended superstrings can be embedded in (N+1)-extended superstrings. In other words, (N=0, c=26)→(N=1, c=15)→(N=2, c=6)→(N=3, c=0)→(N=4, c=0). In this paper, we show that similar embeddings are also possible for N-extended superstrings at non-critical central charge. For any x, the embedding is (N=0, c=26+x)→(N=1, c=15+x)→(N=2, c=6+x)→(N=3, c=x)→(N=4, c=x). As was conjectured by Vafa, the (N=2, c=9)→(N=3, c=3) embedding can be used to prove that N=0 topological strings are special vaccua of N=1 topological strings.