James Murray et al - A New English Dictionary on Historical Principles (1888)
Official website
Prefaces to the First Edition
Early edition volumes:
Volume 1
Volume 2
Volume 3
Volume 4
Volume 5 Part 1
Volume 5 Part 2
Volume 6
Volume 7
Volume 8 Part 1
Volume 8 Part 2
Volume 9 Part 1
Volume 9 Part 2
The fourth in The Guardian's list of Top 10 Dictionaries is perhaps the best known: The Oxford English Dictionary. Partly that's the name recognition (who other than literary people know the controversy about the Webster Third?) but also because it was the subject of a bestseller (Simon Winchester's The Professor and the Madman). By any standard it's a remarkable work of scholarship even if not for casual use.
The links above I marked as "early edition" though I think they actually are all to scans of the first edition which came out over several years. However one major problem of online libraries is that they don't handle multi-volume works well so those links go to a combination of sources. I also didn't expect them closely but they all appear to be the correct volume number. Most libraries of any size have a print copy and many now have the current OED available online.