You can recommend a book to another user and other users can make book recommendations to you. Book recommendations can be done in two ways:

First, locate the item you want to recommend using a search or clicking through to it on your bookshelf, then click the “Recommend this item” icon next to it:

Next you have to choose the user you want to recommend this to; use the search box that displays on the page, and once you've found the right user, click the “Select user” icon:

You then have the option to enter personal text to appear with the recommendation:

Once you've sent the recommendation, the user will see a notification for it when they log in:

First, find the user you want to recommend a book to (for example, by searching or clicking through from your friends list), go to his or her profile and click the “Recommend to a friend” icon by their picture:

Next, choose an item from your bookshelf or search for an item to recommend, then select it using the “Choose item” icon:

Then you have the option to enter a personal message to add to the recommendation; do this if you wish, then click the “Recommend” button:

Once the recommendation has been sent, the user will see a notification for it when they log in:

From your own profile box, you can follow a link to “Recommendations”. This will display two boxes:

The “Recommendations to me” box, which shows all the recommendations you've received from other users:

And the “Recommendations I made” box, which shows all the recommendations you have made to other users:

When you view someone else's profile, you can click the “Recommendations” link in their profile box to see two lists:

The “Recommendations user made” box:

And the “Recommendations I made” box: