Accidental surfaces in knot complements

It is well known that for many knot classes in the 3-sphere, every closed i ncompressible surface in their complements contains an essential loop which is isotopic into the boundary of the knot exterior. In this paper, we inve stigate closed incompressible surfaces in knot complements with this proper ty. We show that if a closed, incompressible, non-boundary-parallel surface in a knot complement has such loops, then they determine the unique slope on the boundary of the knot exterior. Moreover, if the slope is non-meridio nal, then such loops are mutually isotopic in the surface. As an applicatio n, a necessary and sufficient condition for knots to bound totally knotted Seifert surfaces is given.