I can recomend the paper

  "The Paradigm Shift from Algorithms to Interaction"
  by Peter Wegner, Brown University.

  http://www.tiac.net/users/jsuth/papers/wegacm.pdf

While some people have nasty things to say about this paper
in particular and about the author's ideas in general, I
really liked it and think it is a good argument about why
objects have been much less "formal" than computing in
general so far (and also why they are more powerfull).

Cheers,
-- Jecel