The Internet Archive is a San Francisco–based nonprofit digital library with the stated mission of “universal access to all knowledge.” It provides free public access to collections of digitized materials, which includes websites, software applications, games, music, movies, videos, moving images, and tens of thousands public-domain books. The Internet Archive’s collection is growing daily and best of all, it is FREE. Go ahead and create a user name and password. If you log in, it makes it easier to download books, save books and mark "favorites".
The Internet Archive has a dedicated section just for genealogy, family history, and local history books. You can search that collection from this link: https://archive.org/details/genealogy
Find the box labeled “Search this Collection” (on the left) and search for an ancestor’s full name, just the surname or a place – counties seem to return the most results.
The books that will come up for you to choose from are generally books that contain that ancestor’s name, books about that family’s genealogy or local history books that have that name someplace within the book. Sometimes it will show books written by authors with that surname. If you search for a location you are likely to see county histories which often contain “sketches” about people and/or towns.
The search seems to work best for surnames of families that have been in North America for a century or longer. It does not does not work well for recent immigrants. The reason for that is because the books on this site are out of copyright, which means they were published before 1923. So, don’t look for recent immigrant families in this collection.
Once your search term has returned a page of selections, you can hover your pointer over the book cover to see a short description about the book. There is also a highlighted area (usually in orange) that will show the name or place you searched for.
One a book of interest is located, click on it to "read" it. It will open to show the cover of the book. The blue pointers across the bottom show which pages contain the name or place originally searched for. Hover over the blue marker to see what is contained on each page.
Use the controls along the bottom right to zoom in or out, turn the page either direction or have it read out loud if you want. Hover your pointer over them to see that they do.
If there are a multitude of blue markers, try clicking the far right edge of the book to get to the last page and then use the navigation arrow on the bottom left to page back to an index – hopefully there will be one. Additionally, along the left side there will be a listing of the name found and the pages it is on. You can go down the list and click the page that insterest you.
It is possible, in many cases to download the whole book. Go to the white section below the book and page down. If you are allowed to download the book, on the left you will see choices – PDF, Kindle, etc. Chose what suits your needs and click on that choice. It might be handy to have to book on a local computer for quick reference – especially if you are lucky enough to find a family tree going back many generations.
You can go back to the original page of books that met your search criteria by clicking on your “browser’s back arrow” (top left).
If you do not find what you are looking for you should also search at the overall resource, https://archive.org
. There will be a much larger selection and many will not pertain to genealogy or history.