Review

I finished reading a book this weekend. The book is "The Door into Summer". 　Robert A Heinlein wrote this book in 1956. He is one of the most famous SF novelists in the world and this book is very famous.



I tell the story simply. The theme is time travel. In this book, technology is more developed than the real world. The hero, Dan in is an engineer. He invents a lot of great machines. He made robots. They can clean room, wash dishes, speak, and look after children. They can do all things which are human can do. However he is deceived and almost robbed the robot's plan by his friend and his girlfriend,so he dispose of the plan. Dan is disappointed and decide to take the cold sleep. This is happened in 1970.



The cold sleep is one of the way of time travel, but this way is only used to go to future. This make human the status like hibernation and when they notice, they are in the future without older. In real world, a company invented a device to use cold sleep in 2014. If you are interested let's search cold sleep on the internet. There are many piece of information. It is famous for SF fans and researcher.



I continue to tell the story about The door into summer. When Dan wake up, he is in the world of 30 years later.  It is very developed. He lived there for a while and notice the robot which  he try to make is used in the world. Dan examine the reason why the robot exist and he know that Dan invented the robot in 1970. It was impossible. To know the truth, he decided to back to the world in 1970.



This is very nice book for me. Characters in this book is very interesting. The quarrel between Dan, to his friend and his girlfriend is very exciting, but the last is a little bad for me because I think the novelist gave up to explain a contradiction. I want a more clear reason. This is closely involved  the story so I don't tell in details. I borrowed this book in library in Hiroshima university, If you are interested in this book, please read this. Library is very useful because we can read a lot of books freely.