For a smooth map between noetherian schemes, Verdier relates the top relative differentials of the map with the twisted inverse image functor "upper shriek" [V]. We show that the associated traces for smooth proper maps can be rendered concrete by showing that the resulting theory of residues satisfy the residue formulas (R1)-(R10) in Hartshorne's Residues and Duality [RD]. We show that the resulting abstract transitivity map relating the twisted image functors for the composite of two smooth maps satisfies an explicit formula involving differential forms. We also give explicit formulas for traces of differential forms for finite flat maps (arising from Verdier's isomorphism) between schemes which are smooth over a common base, and use this to relate Verdier's isomorphism to Kunz and Waldi's regular differentials. These results also give concrete realisations of traces and residues for Lipman's fundamental class map via the results of Lipman and Neeman [LN2] relating the fundamental class to Verdier's isomorphism.All schemes formal or ordinary are assumed to be noetherian. The category of O X -modules for a formal scheme X is denoted A(X ) and its derived category D(X ) as in [NS1]. In general we use the notations of ibid. Thus the torsion functor Γ ′ X on O X -modules is defined by the formulawhere I is any ideal of definition of the formal scheme X . A torsion module F is an object in A(X ) such that Γ ′ X F = F . The reader is advised to look at [NS1, § 2] for further definitions and notations, especially the definitions of A c (X ), A c (X ), A qc (X ), A qct (X ), and the triangulated full subcategories of D(X), D c (X ), D c (X ), D qc (X ), D qct (X ), and their various bounded versions (e.g., D + c (X ) . . . ).