If you are unfamiliar with the game of Texas Holdem, please first read the article entitled Texas Holdem, then return here for specific distinctions of Limit Texas Holdem.
The small blind in Limit Texas Holdem is equal to half the lower betting limit and the large blind is equal to the lower betting limit. For the first two rounds of betting, players can only bet/raise the lower betting limit. For the last two rounds of betting, players must bet/raise the upper betting limit. (ie. In a $5/$10 game: the small blind is $2.50, the big blind is $5, bets and raises for the first two rounds are $5, bets and raises for the last two rounds are $10.)
In each round of betting there is a maximum of one initial bet and three raises. The exception comes when just two players face each other in heads-up (one-on-one) action. As long as the action becomes heads-up before the betting/raising is capped, the two heads-up players are permitted to raise an unlimited number of times.
In Limit Texas Holdem if a player goes all-in with less than half of the required minimum bet/raise, subsequent players who are in the pot for all previous bets and who have already acted in this round of betting may NOT make a full raise. They can only fold, call, or complete the bet, raising just the necessary amount to bring the all-in player's incomplete raise up to the required amount. Thus in a $10 betting round, a player can only raise a $4 all-in bet to $10. If a player goes all-in with at least half the required bet, subsequent players are permitted to make a full raise. Thus in a $10 betting round, a player can raise a $7 all-in bet to $17.