Perelandra is written of a completely different tone that than of Out of the Silent Planet. This time, the professor launches himself into space because he had a dream about going to Venus, which is really Perelandra.
Perelandra is just beginning to be inhabited by life. The planet is a sea of floating islands. The islands are like ships. On one of these, he meets a green woman leading animals around.
There is really no plot structure to this book; it consists of philosophical conversation between the professor and the green woman as she shows him around the planet. This does not hold the reader's attention very well and doesn't really seem like a fiction book. It seems like Out of the Silent Planet could have stood alone and perhaps be expanded upon.
The end of the book shows the professor fighting with the Satan character, who is trying to get the green woman to succumb to his lies so that he can rule Perelandra too. since the professor knows what happened on Earth, he knows he must try to stop him. This is the most interesting part of the book because it asks the question "What if someone stopped Eve from taking the fruit?"
However, it seems like Lewis wrote the book for the end and filled up the rest of the book with philosophy.
All in all, the book is interesting if you like that type of thing. The whole idea is original, but it isn't handled correctly. This is one of the rare books by C.S. Lewis that I do not like as much.