A crucial step in the surgery-theoretic program to classify smooth manifolds is that of representing a middle-dimensional homology class by a smoothly embedded sphere. This step fails even for the simple 4-manifolds obtained from the 4-ball by adding a 2-handle with framing r along some knot K → ∂B 4 . An r-shake slice knot is one for which a generator of the second homology of this 4-manifold can be represented by a smoothly embedded 2-sphere. It is not known whether there exist 0-shake slice knots that are not slice. We define a relative notion of r-shake sliceness of knots, which we call r-shake concordance which is easily seen to be a generalization of classical concordance, and we give the first examples of knots that are 0-shake concordant but not concordant; these may be chosen to be topologically slice. Additionally, for each r we completely characterize r-shake slice and r-shake concordant knots in terms of concordance and satellite operators. Our characterization allows us to construct new families of possible r-shake slice knots that are not slice. Rice University). K denote the 3-manifold obtained by performing r-framed surgery on S 3 along the knot K.Recall that the classical concordance invariants are determined by the homology cobordism type of M 0 K , along with the homology class of the positive meridian. Hence the question of whether there exist 0-shake slice knots that are not slice is especially difficult because there are presently no known invariants that can distinguish between a knot being slice in B 4 and it being slice in merely a homology B 4 , except (possibly) Rasmussen's s -invariant and its generalizations.Therefore, it may be surprising that here we find success in the relative case.Theorem 4.1. For any integer r, there exist infinitely many knots which are distinct in smooth concordance but are pairwise r-shake concordant. For r = 0, there exist topologically slice knots with this property as well. In addition, for any integer r, none of τ, s , or slice genus is invariant under r-shake concordance.This result can be seen as a consequence of our complete characterization of r-shake concordance in terms of concordance and certain winding number one satellites. Let P be a pattern knot, that is, a knot inside a solid torus (an example is shown in Figure 1). For any knot K, let P r (K) denote the r-twisted satellite of K with pattern P [27, p. 10, 37, p. 110]. The symbol P (K) denotes the 0-twisted (that is, classical) satellite of K with pattern P . Let P denote the knot in S 3 given by P when the solid torus is placed in S 3 in the standard unknotted manner, or equivalently, P = P (U ), where U is the unknot.Theorem 3.7. For any integer r, the knots K and J are r-shake concordant if and only if there exist winding number one patterns P and Q, with P and Q ribbon knots, such that P r (K) is concordant to Q r (J).Corollary 3.9. For any integer r, the equivalence relation on the set of knots generated by r-shake concordance is the same as that generated by concordance together with the ...