1.First go to Google Book Bar Wizard.
2.Now Customize your Book Bar.
3.Enter your blog URL.
4.Click on generate code.
5.Now copy generated code.
6.Login to your blogger dashboard--> layout- ->Page Elements
7.Click on 'Add a Gadget' on the sidebar.
8.Select 'HTML/Javascript' and add your Book Bar code and click save.
Now you are done.