For a more modern car, it's possible to get a reasonable history (depending on how much information was input) by getting a CARFAX or something similar on it. I bought their unlimited VIN look up a while back and ran all of my old VINs, just to see where the cars ended up. Rather interesting, actually.
As far as the antique cars, it's not nearly as easy. Unless the paperwork was kept with the car, you're pretty much out of luck. I've tried researching one of my cars and I had some hits from the internet. However, what I really wanted to know was the first owner. The local paper for where it was sold actually listed serial numbers (engine numbers) and buyers, but alas...I could never find the one I own.
I'm a historian (have published a few books, in fact) so I enjoy learning the history of my cars. Sometimes, however, the story just ends without satisfaction.