You can access their catalog here . Of course, the Library of Congress is the largest library in the world. You can access their catalog here . For regional research, try the nearest academic or public library, large or small. They almost certainly make a special effort to collect resources about local and regional history.
National libraries are also an excellent place to look for information on a specific country.
Other specialized library catalogs Institute of Marine Engineers has a very specialized library collection of over 10,000 volumes. You can access their catalog here . Remember that there are many other libraries that might be of use, but these will be a good place to start. The database section of my webliography lists free databases available on the internet. A lot of maritime museum libraries do not have their holdings in a web-accessible format.