But here's my best effort to make sense of one.
Try to imagine for a moment what the world of 1985 looked like to someone born in just before the turn of the 20th century, in 1899. The Old Timer's life was like that but even more so. The 21st century turned out to hold even more changes for humanity than the previous one.
No one had been in the Space Service longer than he had, the Old Timer was present right at the founding. With almost fifty years in, everybody assumed that he used some sort of secret clout to stay on active duty long after the mandatory retirement age. Every year on his birthday he would go to the officer's lounge and chew the fat with the latest batch of academy brats. He would amaze them of tales of the Bad Old Days. Those kids would be amazed to hear of a world without interstellar travel. When he was a kid on one system was inhabited by humans, not the forty we have today! And on Earth instead of a unified planetary government we had dozens of independant political units! Terraforming hadn't been invented yet, so everyone breathed poisoned air, even on the planet we evolved on!
Once, a few birthdays back, he mentioned that his favorite change were the six Earthlike worlds with proper stocks of fish. He could catch a salmon or tuna and chop it up for sushi right on the spot. A terrible slip. The Old Timer had forgotten that meat eaters were considered something like serial killers these days. Fortunately he knew one of the captain's fathers and the incident hadn't been reported. There's no such thing as a fishing license on any of the Earthlikes and his little sushi expeditions were all technically criminal.So that's the gist of the dream, minus the crazy stuff like the fact that the officer's lounge on an exploration spaceship happened to look exactly like my high school chemistry lab, or that the redheaded gal playing Danny Boy on the piano wore here keyboard around her waist, like some sort of portable Sy Snootles gear. Oh, and computers were no longer called computers. They were all "googles". Load the Navigation program into the Google-3, we're ready to plot our jump.
But anyway, the basic idea seems to have been that we go from the world we know to a standard Traveller single subsector set-up in the course of one lifetime. The oldsters in the campaign would remember the bygone days of Britney Spears and reality TV, but everyone would live in a world much more like Star Trek: The Next Generation.
AD&D Monster Manual part 57
54 minutes ago