Robert A. Heinlein was a very smart man who liked to write books. A bibliography is a list of all the books that someone has written. So, a Robert A. Heinlein bibliography is a big list of all the books he wrote.
Some of his most famous books are about space adventures and people who travel to different planets. He wrote these books a long time ago, before people had even gone to the moon. That makes him a special writer because he had to imagine what it would be like to travel in space before it was even possible.
In his books, Robert A. Heinlein talked about things that all people care about, like being brave, helping others, and sticking up for what you believe in. Some of his books are very long and some are very short, but they all have interesting stories to tell.
If you want to read some of Robert A. Heinlein's books, you can look at the bibliography to see which ones he wrote. Then you can go find those books at your library or bookstore and see what adventures await you in space!