I'm looking for letters from British soldiers in the British Mandate of Palestine. The book I'm currently reading has lots of letters cited/quoted, so I know they're out there, but more often than not they're in British universities (I'm in the US).
Would HathiTrust Digital Library be a viable place to look? I vaguely remember hearing that name, but a cursory look for sources didn't really turn up much and I'm wondering if digging deeper is worth the time/effort. Also I have access to a really wide variety of databases through my university, so it's more likely than not that I can reach them. Any help would be much appreciated!
So you have citations to the letters with their library locations listed? The best place to start is the websites of those libraries. See if they have "digital collections" or a "digitized manuscripts" section. If not, go to their "Special Collections" page or whatnot. At some point on the site, at some level of the site's organizational hierarchy, you'll find either a webpage devoted to the Ron Swanson Memorial Letter Library, or just a search form where you can enter the shelf marks for manuscripts in the library. That's how you'll find out if they've been digitized by the library that holds them.
You should also make really good friends with the Interlibrary Loan staff at your university. They may have contacts with the university library that holds the letters. Depending on the fragility of the letters and preservation needs, your ILL people miiiight be able to work Real True Miracles and get you some CD-ROM or flash drive scans of the letters. That's kind of a specialized service, though, usually reserved for just a handful of super-qualified people. But it's always worth a shot!