def author_search(author, mode='books', weight=HEAVY, page=1,
sort_type=nil, offerings=nil, keyword=nil,
price=nil, editions=SINGLE_EDITION, &block)
url = AWS_PREFIX + "?t=%s&AuthorSearch=%s&mode=%s&f=xml" +
"&type=%s&dev-t=%s&page=%s"
url << "&price=" << price unless price.nil?
url << "&variations=yes" if editions == ALL_EDITIONS
url << get_offer_string(offerings)
sort_string = get_sort_string(sort_type, mode)
@type = WEIGHT[weight]
author = url_encode(author)
raise ModeError, 'mode must be books' unless mode == 'books'
mode = localise_mode(mode)
url = url % [@id, author, mode, @type, @token, page] << sort_string
search(url, &block)
end