Reading 3 books will make us an expert in a topic. Once we pick a topic that interests us, or decide on a topic that we want to become an expert, how do we choose those three books?
I would strongly encourage you to get a membership at your local library. While there, look in their book catalog for the topic you are interested in.
It is possible they will only have three books on that topic.
Or they might have more. Many more.
When you include books they can get from sister libraries and InterLibrary Loan, the number jumps by leaps-and-bounds.
Fortunately, there is help. An organization called The Browser has asked experts in their field what Five Books they would recommend others to read. After each recommendation, the site also allows others to comment on books not on the list that they would recommend as well.
You may not find your topic there, but at least it is a start.
What topic are you researching? Have you found any good books you can recommend to others?