Bruji

I just searched for John Battelle's book The Search through Bookpedia, choosing amazon.co.jp as the site to search. The keywords I put in were "battelle search".
I got 4 results: Diet Revolution by Barry Sears; The Baby Book by William Sears; Tips for child raising by Martha and William Sears; and some book by Margaret King Sears.
If I do the same search in a browser at amazon.co.jp I get 4 results, and they're all different editions of the book The Search by John Battelle.
It's no great hardship to ignore Bookpedia's search function and search directly on Amazon Japan, but I wonder why Bookpedia's results are all books that don't contain any of the search terms. Are there any tips for better searching with Bookpedia?

Amazon makes a distinction between foreign books and regular books. Make sure to set the search type to foreign books right next to where you select the amazon.jp site, when looking for English books.