Many people don't know that you can give Kindle books as gifts to people. All you need is the person's e-mail address. On the right-hand panel of the Kindle book you have chosen there is a button that you can press to give the book as a gift.
Press it, enter the person's e-mail, and give them a nice surprise. All they will need to do is follow the link in the gift notification e-mail they will receive from Amazon and press the "Accept gift" button. Then, the book will arrive on their Kindle.
I just got my first Kindle book gift, so I'm very excited.