Ask for it by name, or cite the Diamond Code AUG100733 if your comic store doesn’t have it. In a regular bookstore, cite ISBN 978-1593622022.
Alternatively, you can order the book online from amazon.com or direct from SLG. Or, in Canada, amazon.ca, or in Japan, amazon.co.jp.Int he UK, your best bet is probably Forbidden Planet. In Australia, if you can’t get to a comic store try Minotaur’s online shop.
You know what to do.