Blackjack, also known as Twenty-One, is a card game where to rules are quite simple. The player must beat the dealer. A simple task for a expert player who knows the game and maybe is able to count cards. But even for a casual player a very attractive game to play, because the odds of the casino are less. The history of this game goes way back, to the 1960s, where to first rules were made in France. At this time Blackjack was called Vingt-Un what means Twenty One in French. At the moment Blackjack is a card game that cannot be missed in every American Casino or online gambling sites.
For Blackjack the standard 52-card pack is used, but in the most casinos more decks are used and are shuffled together. Mostly six decks are used to form "The Shoe" that contains 312 cards in total. In addition, the dealer uses a blank or colored card - the cutting card -, which is never dealt, but is placed in the middle of the shoe. When the dealer deals the cutting card than it will be time for the cards to be reshuffled.
Each participant individually tries to beat the dealer by getting a score as close to 21 as possible. The participant is not allowed to get over 21. When that happens he busts and lose that hand regardless of the outcome from the dealer.
All numerical cards are representing that value. Face cards are worth 10, except the ace. The player can choose whether the ace has a value of 1 or 11.
Before the deal begins, players has to place a bet. The bet must place in front of the player, in a designated area. Minimum and maximum limits are established on the betting, which can be different per casino or site.
When everyone has placed their bets, the dealer gives one card face up to each player who has placed a bet. Starting with the player to the left of the dealer and following clockwise, including himself. Then, everbody is given another card face up, besides the dealer. His second card will be face down.
If the first two cards of the player are an ace and a "ten-card", then the players count will be 21 or "blackjack". The dealer immediately pays the player one and a half times the amount of their bet. If the dealer also has blackjack, the dealer immediately collect the bets of all players who doesn't. When the dealer and the player both have blackjack, then the bet of the player will be a stand-off (a tie or a push), and the player takes back their bet.

If the first card of the dealer is an ace, the dealer look at their face-down card to see if the two cards make a blackjack. If it makes a blackjack, the dealer will turn their face-down card and all the players who doesn't have a blackjack lose. If the second card is not a ten-card, the game continues.
The player to the left goes first and must decide whether to stand or hit (ask for another card). The player can hit aslong as the score of the cards is under 21. If the score goes above 21, the player busts and loses its bet. The dealer then turns to the next player.
When the dealer has served every player, his face-down card is turned up. If the total of the cards is 17 or more, it must stand. If the total of the cards is 16 or under, they must take a card. The dealer must continue to take cards untill the total of the cards is 17 or more. If the dealer has an ace and the total of the cards is 17 or more, then it will count as 11 and the dealer must stand. If the dealer, for example, has 13 after his two cards and then draw an ace, it cannot count for 11 anymore because he would then have a score of 24. It automatically counts for 1 and the dealer must take another card, because his score is 14. If the dealer must stand the game ends and it all starts over again after the next bet has been accepted.
When the first card of the dealer is an ace, the chance it having a blackjack are high. Any of the player are then able to ensure their hand by paying half of their original bet. If the face down card of the dealer is a ten-card, it is turned up, and those who have made the insurance bet win and are paid the original bet plus the insurance bet.
If a player's first two cards are of the same denomination, such as two queens or two eights, the may choose to split and threat them as two seperate hands. The amount of the original bet then goes on one of the cards, and an equal amount must be placed as a bet on the other card. The player first plays the hand to their left, the hand to their right will be played afterwards. If a player's first two cards are two aces, the still may choose to split, but the player is given only one card for each ace and may not draw again. If a ten-card is dealt to one of these aces, the payoff is equal to the bet and will not be treated as a blackjack.

Side note: Sometimes it is also possible to split two ten-cards even if they are not the same. A king and a queen for example.
Another option a player has is to doubling their bet when to original two cards dealt total 9, 10 or 11. They place a bet equal to the original bet and the dealer gives to player just one card. Side note: Sometimes it is possible to double down at any time, but that varys per casino or site.
At some casinos or sites the player is able to place additional bets before the start of a standard game. They involve predicting which cards the player, and sometimes the dealer, will receive. These additional bets are called Side Bets and mostly consist of "Perfect Pair" and "21+3". These are clearly marked either printed on the Blackjack tables or available as a hand out or a side menu in the online version, mostly left and right from the main bet.

Perfect Pair
This side bet uses the player's cards only and pays out if you are dealt two cards that are the same denomination, such as two eights in this case. Their are three possibilities.

Name Explanation Payout
Mixed pair Two of the same value, but different suit and color.
For example: 8 8
5 to 1
Coloured pair Two of the same value and color, but different suit.
For example: 8 8
12 to 1
Perfect pair Two of the same value. color and suit.
For example: 8 8
25 to 1
21 + 3
This side bet involves the player's two cards and the face-up card of the dealer. It will pays out for various combinations.

Name Explanation Payout
Flush All the cards are the same suit.
For example: 8 5 J
5 to 1
Straight All cards consecutive, but different suits.
For example: 8 910
10 to 1
Three of a kind All cards are the same value, but not the same suit.
For example: 8 88
30 to 1
Straight flush All cards are consecutive and the same suit.
For example: 8 910
40 to 1
Suided trips All cards are the same value and the same suit.
For example: 8 88
100 to 1