These are the requirements for your book sales tracking and shopping cart mashup:
Provide information on the book
Track and chart the sales of the book through the online book seller
Provide customer reviews on your site to show customer feedback that is posted on the online book seller
Provide a shopping cart that is integrated into your website that enables visitors to your website to buy your book easily
Allow visitors to your website to also buy related books through your website in order for your to earn some extra income from product recommendation