Let Γ be a connected component of the Auslander-Reiten quiver Γ (mod A) of an Artin algebra. We show that Γ is quasi-directed if and only if the paths in ind A, having end-points in Γ , satisfy certain conditions. Moreover, we describe the shapes of such components and identify the classes of algebras to which they are related. 2004 Elsevier Inc. All rights reserved.Let A be an Artin algebra. We are interested in studying the representation theory of A, thus in characterizing A by properties of the module category mod A of finitely generated right modules. One way to achieve this goal is to take a look at the paths in ind A, a full subcategory of mod A consisting of one representative from each isomorphism class of indecomposable modules. For instance, the quasi-tilted algebras [14], the shod algebras [9,21], the weakly shod algebras [10,11] and, recently, the laura algebras [2,22,33] are several important classes of algebras which have been totally characterized by properties of paths