public function ItemSearch($keywords, $searchIndex = NULL, $sortBy = NULL, $condition = 'New') {
		$params = array(
			'Operation' => 'ItemSearch',
			'ResponseGroup' => 'ItemAttributes,Offers,Images',
			'Keywords' => $keywords,
			'Condition' => $condition,
			'SearchIndex' => empty($searchIndex) ? 'All' : $searchIndex,
			'Sort' => $sortBy && ($searchIndex != 'All') ? $sortBy : NULL
		);

		return $this->MakeAndParseRequest($params);
	}