language = book['language'] === 'en'? 'English' : 'unknown'
    type = book['printType'] === 'BOOK'? 'paperback' : 'unknown'
    isbn10 = get_isbn(book, 'ISBN_10')
    isbn13 = get_isbn(book, 'ISBN_13')

    return {
        'id' => id,
        'author': book['authors'][0],
        'year': book['publishedDate'],
        'type' => type,
        'pages' => book['pageCount'],