Want to recommend a book to someone? Go buy it and send them their way. With eBooks now, I add into the contact card of a person if they prefer a format or other. For example my friend A reads on Kindle as well as T. My friend S and C use the Apple iBooks and my friend K the Nook.
When I want to send them a book, I know the format and can simply send it their way. When in doubt send a paper one.
Receiving a book is one of those things that make you smile, can change your mind, or give you hours of entertainment and answers.
Don’t recommend a friend that they go and read that book you just finish and loved. Send it their way.