As far as preparation for the lactation exam, I did use Riordan & Aurbach,
but would also recommend "The Breastfeeding Answer Book" by LLL.  It has alot
of information and is easy to read.  By the way there is a 1997 edition, I
would get that one. If anything, it is the most superb reference that you
will use non-stop in your practice(whatever that may be).
  It, however, does not have any photographs, so it would be beneficial to
have the Auerbach,Riordan book.
  Hope this helps, and Good Luck on the test.
  Sincerely, Linda Marie Bradley, RN,BSN,IBCLC