Books are not in danger of becoming obsolete, because we still read books even though there are electrical books now. One of the issues about books is that they are changing to electrical books. iPad and other products are introduced to read the books electrically. However, people would still feel more comfortable reading paper books. Digital books could be efficient, because of the size and weight, but it would still need time to spread the technology.
Most people still read paper books and they are happy by the situation. Some people might use the public library to borrow the books and they are free. It would be more expensive to buy the products for digital books now so that the customers are waiting for the price to go down.
The digital books can be useful, because they can download the books for iPad or other products to read, but we still do not feel it is natural to read the books digitally. Some people prefer paper books, because they like the smell of paper.
In conclusion, paper books will not be obsolete soon, because people still prefer reading the paper books than digital books. If the prices of digital books become cheaper, the customers might change their attitude and start reading the electrical books.