Minimum Pages Needed
1. Welcome page
2. How to get in touch with you. This can be an About You page with a brief biography, but the important thing is to include a contact form or email address that can't be harvested by hackers. That usually means an address written out, not posted as a hot link. Example: Joan at JoanReeves dot com.
3. Your published books. Show the covers and give buy links for each.
Include anything else you think your readers would like to know about you. Make the content entertaining and interesting.
A static website is a good tool and one that doesn't require continuous posting of new content.