setApplicationName("BookInventory"); $client->setDeveloperKey(env('GOOGLE_BOOKS_KEY')); $service = new Google_Service_Books($client); $results = $service->volumes->listVolumes('isbn:' . $isbn); /** * @var \Google_Service_Books_Volume */ $volume = array_first($results->getItems())->getVolumeInfo(); return [ 'title' => $volume->getTitle(), 'authors' => $volume->getAuthors() ]; } }