We investigate codimension-one
imbeddings of punctured lens spaces and connected sums of lens spaces. For |π1(L)| a
prime power we show that L − B2k−1 imbeds in S2k if and only if L is of a
certain special form. If L#L′ imbeds in S2k, then L ≃ L′ and L is homology
cobordant to L′. For |π1(L)| a prime power, this implies (via Smith-theory) that
L≅L′.