The words that I underlined are, in my opinion the key words

The book of the future

There are a number of reasons why computers won't replace books entirely. One reason is that books on paper are much cheaper than computers. Books don't need a power source¹ either. You can read a book for as long as you want and wherever you want. You never have to worry about losing power. Also, many people feel more comfortable reading words in a book than reading words on a computer screen. It's less tiring to the eyes.
Will books in the future be similar to the books you can buy today? The answer to that question is no. In the future you may only need to buy one book. With this one book, you will be able to read novels, plays, end even today's newspaper. It will look like today's book, but it will be electronic².
One of the people working on the book of the future is Professor Joseph Jacobson from the Massachusetts Institute of Technology in the U. S. Professor Jacobson's book will have a small button on the side. When you press the button, words will instantly appear on the page. When you want to read a different story, you can push the button again and a new story will quickly appear. What is the technology behind Professor Jacobson's book? Two important inventions will make this new kind of book possible: electronic ink and radio paper. Electronic ink - or "e-ink" - is a liquid that can be printed on paper, metal, or anything else. E-ink looks and feels like printed words on paper. Unlike regular ink, however, words in e-ink are not permanent. They can be changed by pushing a button. When you push the button, all of the words on the page go away and new words appear.
The other new development is radio paper. This paper looks and feels like a page in a book. In reality, however, radio paper is made of plastic.
Professor Jacobson calls his book of the future "the last book". This book, he says, will be the last book you will ever need. .

The book of the future

There are a number of reasons why computers won't replace books entirely. One reason is that books on paper are much cheaper than computers. Books don't need a power source either. You can read a book for as long as you want and wherever you want. You never have to worry about losing power and the computre is less tiring to the eyes. In the future you may only need to buy one book. With this one book you will be able to do everything. This book will look like today's book, but it will be electronic.
Professor Joseph Jacobson is an American doctor who is working to make this incredible book. Professor Jacobson's book will have a small button on the side. With this button you can do everything: you can appear the words on the page and you can change the story that you want to read. Behind this book there are two important inventions: electronic ink and radio paper. Electronic ink  is a liquid that can be printed on anything.  Unlike regular ink, however, words in e-ink are not permanent.
The other new development is radio paper. This paper looks and feels like a page in a book. In reality, however, radio paper is made of plastic.
Professor Jacobson calls his book of the future "the last book" because it is the last book that you will buy.