Physical interpretation of Ewald summations

["Dillen J, Prof" <jlmd.,at,.maties.sun.ac.za>]

Hi,
 Is anyone aware of a book or article on the
 physical interpretation of Ewald summations?
 I am not looking for a detailed description
 of the mathematics (I have plenty of those), but
 for a text that explains at a level suitable for
 say an M.Sc. student (1) why the lattice summations
 actually converge faster and (2) what the physical
 meaning is of summing interactions in reciprocal space.
 I have copies of the papers by Nijboer & de Wette and
 by D. Williams but they offer answers to "how"
 rather than "why". I also have access to Kittel's book
 "Solid State Physics"  but as with the articles above,
 although probably more readable for the average student,
 it is presented as a mathematical trick.
 Jan Dillen
 Stellenbosch University