How to Buy In USA.
ISBN Numbers
Paperback: ISBN: 978-0-2288-5161-5
Hardcover: ISBN: 978-0-2288-5162-2
Ebook: ISBN: 978-0-2288-5163-9
From your local bookstore
Just head down to your local bookstore and quote the relevant ISBN number for the edition you want. Alternatively you could show your book seller the For Booksellers page from this website.
Online
Amazon (Paperback, Hardcover, Kindle)
Barnes & Noble (Paperback, Hardcover, Nook)
EBook (Kobo Edition)
EBook (Smashwords Edition)