Google has produced many valuable search aids, Google Scholar not least among them. For this particular course you may find Google Book Search especially useful. If you have used this search interface extensively, especially the "Advanced Search", you will probably be familiar with the information on this page. If you have not, you will find some very helpful tips here.
Google Books can be used to find libraries that hold a specific title or to find bookstores that can sell you a copy of a book. They can also be used to identify full text online of a work. In some cases, although there may be full text available online, it may only be available on a subscription basis. A great deal of full-text material is available to all users.
The search pictured below was intended to find any full text written by Tolstoy that included the word "health". If you mark the "Full view" option in the "Search" line (indicated by the red arrow), you will pull up just those hits that have full text, freely available. Without marking this you will find all hits, including those that are only available with limited previews or available at other libraries.
If you think about the contents of books, you can also refine the search to bring up books with illustrations. If you were searching for images of Russian peasants you could do the following:
Now your search will return books with the words peasant and illustrations about Russia with full text available. One of the titles identified was:
Now if you click on "About this book" you will see more information on the book, including some thumbnails of a few of the images from the text. One of the images is pictured below.
The examples above will give you some idea of the many uses for a Google Book Search. This is just intended as a general introduction. More extensive information is available at Google Books. A very good guide is available through the Univeristy of Michigan as well.