You can then save the books you want into your "library". This is a virtual list of the books you want to save in your list. The books can be labeled which allows you to sort the books similar to how you can use tags in Delicious to sort your bookmarks.
As a teacher, I see this as having a lot of potential for teachers and students. As a teacher, I can pre-select books for a class or project and give them all the same label like SSUnit3. I can then sort my library for books with that label. Once I do that, I can copy the URL from the browser window and put them into a wiki or webpage for students to access. They can preview the books, read the ones online that are full text, and plan their reading from any Internet connected computer in the world. Here is an example of the books I have labeled with "Google" in My Library. As I add books with that label, the list is automatically updated for students I have given the webpage URL to.
If you have students who are age 13 or over, they can have their own Google account and create their own library. This could be a way for them to log their independent reading books or develop a reading list for summer. I am sure you all have more ideas, so please share them in the comments below.
Another feature is that you can write a review of the book and read others' reviews. Sounds like an authentic audience for your students to write and submit a book review. For younger students, they could email or word process their review and the teacher could submit it using her teacher account. For older students, they could submit their own.
There are many other features, so I will write about this again as I implement it in my classroom. I plan to try the RSS feed with our LMS as a way to announce new books in the library. I have already used the feature that allows me to "Find in a library" to see if a book I want to read is in a local library. With current budgets at school and home, this is a wonderful feature.
Please comment on more ideas for using this for teachers and students!