  Quasi-alternating links are a natural generalization of alternating links. In
this paper, we show that quasi-alternating links are "homologically thin" for
both Khovanov homology and knot Floer homology. In particular, their bigraded
homology groups are determined by the signature of the link, together with the
Euler characteristic of the respective homology (i.e. the Jones or the
Alexander polynomial). The proofs use the exact triangles relating the homology
of a link with the homologies of its two resolutions at a crossing.
