You can order Barack Obama: This Improbable Quest via Amazon.com by clicking here [1]. You can also order the book directly from Paradigm Publishers [2].
Links:
[1] http://www.amazon.com/gp/aws/cart/add.html?SessionId=105-3031491-7634831&SubscriptionId=D68HUNXKLHS4J&AssociateTag=obampoli-20&ASIN.1=1594514763&Quantity.1=1&adid=02YFW1YNMX4TCG0DYJYF&linkCode=as1&OfferListingId.1=%2FDmxY8RtGDbjOookPwEPgfFWhqE4QlKHKVag%2FqBN%2FzXT4vA8IXNL1jnBDsZLuDRrdM8%2B3ycrRbk1%2BpzUPr0faA%3D%3D&submit.add.x=34&submit.add.y=14&submit.add=Buy from Amazon.com
[2] http://www.paradigmpublishers.com/Books/BookDetail.aspx?productID=168013