Paradiso is a book written by a man named Dante a long, long time ago. The book is about his journey through heaven to get to paradise, which is a fancy word for heaven. In the book, Dante meets lots of important people and learns important and good things from them.
Now, heaven is very special because it's a place where people go after they die if they are very, very good. And it's also a place where they can be close to God. It's like a really good party, but it never ends and everyone is happy and nice to each other.
Dante goes on a journey to get to heaven, but he doesn't go alone. He has a guide with him, named Virgil. Virgil is like a really smart teacher who teaches Dante about heaven and how to get there. They first go to hell, which is a bad place where bad people go when they die. But, after that, Virgil takes Dante to purgatory, which is a place where people go to make up for the bad things they did on Earth.
Finally, after all of that, Dante reaches paradise, or the top of heaven. There, he meets lots of really important people and learns from them. He sees lots of great things and it's really beautiful. Dante is very happy in paradise and he learns how to be a good person so that he can go there too when he dies.