If you were born on Thursday, August 06, 1942 then Henry VIII, I Am by Herman's Hermits was the number one on your 23rd birthday, and went to number one on August 01, 1965. Check the price of Henry VIII, I Am by Herman's Hermits on Amazon.com
The biggest selling book of 1965 (the year you turned 23) was The Source by James A. Michener.