A trusted provider of authoritative books and journals from more than 200 of the world’s most distinguished university presses and scholarly societies. It is weighted heavily toward the hunmanities, so it's a good place, after HOLLIS, to search for the author and topic you're interested in, just to see what (else? more?) turns up.
Familiar and current, it also searches full-text, which makes it different from the other databases (including HOLLIS) on this guide.
Full-text searching can be an advantage when you've got a very narrow topic or are seeking a "nugget" that traditional database searching can't surface easily.
Google Scholar is perfectly acceptable for most general forays into scholarship; its algorithms are excellent and do return relevant results.
NOTE: One simple change can turn Google Scholar into what's effectively a Harvard database -- with links to the full-text of articles that the library can provide. Here's what to do: