  This paper concerns the theory of direct A(d,p)B reactions and how practical
3-body models of them are related to optical model potentials describing the
interaction of the deuteron's constituents and the target A. A new definition
of the nucleon optical potential is introduced which necessitates a careful
examination of the boundary conditions involved in the associate coupled
channels problem. The new definition turns out to be convenient for making a
connection with the theory of the (d,p) reaction. The analysis is carried out
within an antisymmetrised, translationally invariant formalism and provides a
firm basis from a many-body point of view for the three-body force effects
calculated in previous work by Dinmore, Timofeyk, Al-Khalili and Johnson.
