Rehosted from intel.com's archives are two original papers by Gordon Moore. The 1965 paper predicts the ability to cheaply integrate 65,000 devices onto an integrated circuit by 1975 (ten years later). Here is the quote that launched Moore's Law:

"The complexity for minimum component costs has increased at a rate of roughly a factor of two per year (see graph on next page). Certainly over the short term this rate can be expected to continue, if not to increase. Over the longer term, the rate of increase is a bit more uncertain, although there is no reason to believe it will not remain nearly constant for at least 10 years. That means by 1975, the number of components per integrated circuit for minimum cost will be 65,000."

In addition, a wonderful quote we can only wish was still true:

"At present, packaging costs so far exceed the cost of the semiconductor structure itself that there is no incentive to improve yields, but they can be raised as high as is economically justified."

A second paper, from a 1975 speech, notes that "Complexity of integrated circuits has approximately doubled every year since their introduction," but makes a very accurate prediction that continues to hold:

The new slope might approximate a doubling every two years, rather than every year, by the end of the decade.