First, a short history of cards: Playing cards are believed to have been invented in China and/or India sometime around 900 A.D. The Chinese are thought to have originated card games when they began shuffling paper money (another Chinese invention) into various combinations. In China today, the general term for playing cards means "paper tickets".
The contemporary 52 card deck used in the U.S. was originally called the "French Pack" (circa 1600's) which was later adopted by the English and subsequently the Americans. The first records of gambling were in 2300 B.C. or so, and yes, the Chinese again get the credit.
Gambling was very popular in Ancient Greece even though it was illegal and has been a part of the human experience ever since. The history of the BlackJack card game itself is still disputed but was probably spawned from other French games such as "chemin de fer" and "French Ferme".
BlackJack originated in French casinos around 1700 where it was called "vingt-et-un" ("twenty-and-one") and has been played in the U.S. since the 1800's. BlackJack is named as such because if a player got a Jack of Spades and an Ace of Spades as the first two cards (Spade being the color black of course), the player was additionally remunerated.
Gambling was legal out West from the 1850's to 1910, at which time Nevada made it a felony to operate a gambling game. In 1931, Nevada re-legalized casino gambling where BlackJack became one of the primary games of chance offered to gamblers. As some of you may recall, 1978 was the year casino gambling was legalized in Atlantic City, New Jersey. As of 1989, only two states had legalized casino gambling. Since then, about 20 states have had a number of small time casinos sprout up in places such as Black Hawk and Cripple Creek, Colorado and in river boats on the Mississippi. Roughly 70 Native American Indian reservations operate or are building casinos as well.
In addition to the United States, countries operating casinos include France, England, Monaco (Monte Carlo of course) and quite a few in the Caribbean islands.
The first recognized effort to apply mathematics to BlackJack began in 1953 and culminated in 1956 with a published paper. Roger Baldwin wrote a paper in the Journal of the American Statistical Association titled "The Optimum Strategy in BlackJack". These pioneers used calculators and probability and statistics theory to substantially reduce the house advantage. Although the title of their paper was 'optimum strategy', it wasn't really the best strategy because they really needed a computer to refine their system.