The story of Purim is told in the Biblical book of Esther. The heroes of the story are Esther, a beautiful young Jewish woman living in Persia, and her cousin Mordecai, who raised her as if she were his daughter. Esther was taken to the house of Ahasuerus, King of Persia, to become part of his harem. King Ahasuerus loved Esther more than his other women and made Esther queen, but the king did not know that Esther was a Jew, because Mordecai told her not to reveal her identity.

The villain of the story is Haman, an arrogant, egotistical advisor to the king. Haman hated Mordecai because Mordecai refused to bow down to Haman, so Haman plotted to destroy the Jewish people. In a speech that is all too familiar to Jews, Haman told the king, "There is a certain people scattered abroad and dispersed among the peoples in all the provinces of your realm. Their laws are different from those of every other people's, and they do not observe the king's laws; therefore it is not befitting the king to tolerate them." Esther 3:8. The king gave the fate of the Jewish people to Haman, to do as he pleased to them. Haman planned to exterminate all of the Jews.

Mordecai persuaded Esther to speak to the king on behalf of the Jewish people. This was a dangerous thing for Esther to do, because anyone who came into the king's presence without being summoned could be put to death, and she had not been summoned. Esther fasted for three days to prepare herself, then went into the king. He welcomed her. Later, she told him of Haman's plot against her people. The Jewish people were saved, and Haman was hanged on the gallows that had been prepared for Mordecai.

The book of Esther is unusual in that it is the only book of the Bible that does not contain the name of G-d. In fact, it includes virtually no reference to G-d. Mordecai makes a vague reference to the fact that the Jews will be saved by someone else, if not by Esther, but that is the closest the book comes to mentioning G-d. Thus, one important message that can be gained from the story is that G-d often works in ways that are not apparent, in ways that appear to be chance, coincidence or ordinary good luck.

Purim is celebrated on the 14th day of Adar, which is usually in March. The 13th of Adar is the day that Haman chose for the extermination of the Jews, and the day that the Jews battled their enemies for their lives. On the day afterwards, the 14th, they celebrated their survival. In cities that were walled in the time of Joshua, Purim is celebrated on the 15th of the month, because the book of Esther says that in Shushan (a walled city), deliverance from the massacre was not complete until the next day. The 15th is referred to as Shushan Purim.

In leap years, when there are two months of Adar, Purim is celebrated in the second month of Adar, so it is always one month before Passover. The 14th day of the first Adar in a leap year is celebrated as a minor holiday called Purim Katan, which means "little Purim." There are no specific observances for Purim Katan; however, a person should celebrate the holiday and should not mourn or fast. Some communities also observe a "Purim Katan" on the anniversary of any day when their community was saved from a catastrophe, destruction, evil or oppression.

The word "Purim" means "lots" and refers to the lottery that Haman used to choose the date for the massacre.

The Purim holiday is preceded by a minor fast, the Fast of Esther, which commemorates Esther's three days of fasting in preparation for her meeting with the king.

The primary commandment related to Purim is to hear the reading of the book of Esther. The book of Esther is commonly known as the Megillah, which means scroll. Although there are five books of Jewish scripture that are properly referred to as megillahs (Esther, Ruth, Ecclesiastes, Song of Songs, and Lamentations), this is the one people usually mean when the speak of The Megillah. It is customary to boo, hiss, stamp feet and rattle gragers (noisemakers; see illustration) whenever the name of Haman is mentioned in the service. The purpose of this custom is to "blot out the name of Haman."

We are also commanded to eat, drink and be merry. According to the Talmud, a person is required to drink until he cannot tell the difference between "cursed be Haman" and "blessed be Mordecai," though opinions differ as to exactly how drunk that is. A person certainly should not become so drunk that he might violate other commandments or get seriously ill. In addition, recovering alcoholics or others who might suffer serious harm from alcohol are exempt from this obligation.

In addition, we are commanded to send out gifts of food or drink, and to make gifts to charity. The sending of gifts of food and drink is referred to as shalach manos (lit. sending out portions). Among Ashkenazic Jews, a common treat at this time of year is hamentaschen (lit. Haman's pockets). These triangular fruit-filled cookies are supposed to represent Haman's three-cornered hat. My recipe is included below.

It is customary to hold carnival-like celebrations on Purim, to perform plays and parodies, and to hold beauty contests. I have heard that the usual prohibitions against cross-dressing are lifted during this holiday, but I am not certain about that. Americans sometimes refer to Purim as the Jewish Mardi Gras.

Purim is not subject to the sabbath-like restrictions on work that some other holidays are; however, some sources indicate that we should not go about our ordinary business on Purim out of respect for the holiday.