So I tried the "advanced search" for the exact phrase "killing lincoln", it comes back to the regular search page with "killing lincoln" filled in with quotes.
I still get 34 hits. The correct book is in the list but so are many others that have no relationship to the words searched.
Tried "author/title/price" for "Killing Lincoln, O'Reilly and Dugard" and get no hits, none.
Tried "author/title/price" for "Killing Lincoln, O'Reilly" and get four hits all correct.
O'Reilly,Dugard gets no hits.
So it works if I do it right.......