Many people who are not acquainted with the minutea of Barbie doll collecting, yet wish to get into the area so they can sell Barbie dolls for fun and profit, make a very common mistake. They see the copyright date on Barbie of 1966 and immediately think that is the date of manufacture. The 1966 date is actually the copyright date for the mold that Mattel used for Barbie's body and appeared on Barbies made into the late 1990's, if not even later. The same goes for Barbie's boyfriend Ken, who can still show up in stores with a copyright date of 1968. Many people run across Barbies and Kens in a pile with these dates and think they have hit the mother lode. Sadly, these dolls in general are not worth very much and are a very hard sell.

So how DO you know if you have found a vintage Barbie or family member? The easiest way is to check the country of manufacture. If the doll you find was made in Japan, then it is a keeper and comes from either the vintage or mod era of Barbie's existence. There is a wide variance in the value of these dolls, but most everything that was made in Japan has some worth to it (unless it is just in hideous condition).

Addendum:  The following chart can help you narrow down what year a doll was made according to what country the doll was made in.  I thank the folks at dollreference.com for letting me use it here.