Starting a research project? You will need to survey what books may help in your research. Looking for books for the location your ancestor lived in can be a vital first step. Histories, transcriptions, and indexes all need to be consulted. All types of libraries can help you whether public, private, state or academic. How can you search through 1.5 billion items in libraries worldwide?
WorldCat, according to their website, is the world's largest network of library content and services. World Cat allows you to search for books, images, dissertations and more through thousands of libraries worldwide.
Once you find a resource you are interested in, you may enter your location and the website will reveal what libraries "nearby" have the item. You can also sign up for a free account and create a bibliography that can be for your private use or made public and posted to your website or blog.