This is an excellent resource! It should be more popular!

Haathi means elephant in Hindi. I first thought it is to be an Indian site but it is based in the US.

Curious about the connection.

I would use this site all the time for genealogy purposes. It’s hard to unravel how the datasets are shared, because many things here are from Google’s scanning, but IMO there are lots of things that do not appear anywhere else.

We use Hathi a lot at Standard Ebooks as a source of scans to proof productions against. Archive.org has a somewhat better interface, but Hathi has a wider selection.

My family is from Eastern KY and I had access to the HTDL and NYPL through my stint working for a public university a few years ago. It's fascinating what you can find in there! When I had looked a couple years ago it seemed like there wasn't as much publicly available as what I am seeing now.

HathiTrust is much better than Google Books about allowing access to works that are no longer under copyright in the United States. Under US law, everything published 1929 and before is currently in the public domain. But there are a lot of special cases where 20th century works published after 1929 are also in the public domain:

https://guides.library.cornell.edu/copyright/publicdomain

Google Books appears to follow the blanket 1929 rule, or did the last time I looked. HathiTrust has cleared the copyright status for many additional works following the more complex rules, e.g.

"Drawing Birds" by Joy Postle, 1953:

https://babel.hathitrust.org/cgi/pt?id=nyp.33433115876140&se...

Unfortunately, the Google-originated scans that HathiTrust has come with special restrictions. Google itself required that only people associated with the academic libraries could download whole books as a unit, even for works that are in the public domain:

https://hathitrust.atlassian.net/servicedesk/customer/portal...

Fortunately, members of the public can download individual page scans without any special affiliation. People have naturally written tools to automate this process so that full books can be reassembled and then uploaded to the Internet Archive or other book sites.

Google Books has a much faster and sometimes better search interface, so a common flow I use is to search Google Books for terms and then go to HathiTrust to read inside books that Google Books surfaced but won't show.

EDIT: corrected 1926 to 1929 per cxr's comment below.

As a nuclear power historian, this resource is unbelievably valuable. I've been using it for years and it constantly delivers the goods. It contains incredible multitudes.