This year mark's the 40th anniversary of Avalon Hill's Jutland game, which is notable as Jim Dunnigan's first published wargame design.
Dunnigan had written some criticism of the lack of historical accuracy in existing AH games and Avalon Hill decided to give him the opportunity to practice what he preached. While not an academic historian, Dunnigan had the right instincts and did some primary and authoritative secondary source research that made Jutland noticeably more authentic than what had. It led directly to Dunnigan's even more realistic 1914 and his founding of SPI -- developments which changed wargaming for good.
Jutland was never a blockbusting bestseller, but it was in print for most of AH's existence. Naval games have always been a tough sell for wargamers for some reason. While there's a significant faction of naval wargame devotees, most wargamers seem to be landlubbers. Interest in the Great War wasn't as high then, either, as it would later be.
One other factor that held back Jutland's popularity was its miniatures-like game play. While more authentic than using a hex-based battleboard, 1960s-era wargamers were real hex-lovers and anything without hexagons like Jutland faced a real struggle for acceptance.
Still, the game was ground-breaking in many ways and a lot of its concepts influenced later designs, especially naval games. Avalanche Press' Great War At Sea series of games show a clear familial relationship to Jutland.
Jutland was one of my first wargames and the first one to really show me the potential for wargames to illuminate history. While not the most interesting competitive game, Jutland was an informative historical study, best played with a like-minded opponent less interested in winning than in playing the role.
The 1974 rules were more clear and added a couple of badly needed scenarios but made no significant changes to the game. Unlike the slightly older Midway, Jutland hasn't aged quite as well because it's not a great competitive game and newer games have covered the same ground better as historical studies. Avalanche's GWAS series especially exploits the potential that Jutland hinted at, with scores of scenarios and hundreds of ships.
Jutland holds onto a place in my collection as a collectible, and one that still could get played, if only with another old-timer.