Short answers, pulled from the story.
All's Well That Ends Well follows Helena, the low-born ward of a French-Spanish countess, who loves the countess's son Bertram. She cures the ailing King of France and wins the right to marry Bertram, who rejects her; she then follows him to Italy, secretly consummates their marriage, and fulfills the impossible conditions he set before he will accept her as his wife.
The play was published in the First Folio of 1623 and listed among Shakespeare's comedies. The date of composition is debated, with possible dates ranging from 1598 to 1608; scholars Laurie Maguire and Emma Smith argued in 2012 for a date of 1606-1607.
Frederick S. Boas coined the term "problem play" in 1896 to describe All's Well That Ends Well, grouping it with Hamlet, Troilus and Cressida, and Measure for Measure. The category applies to plays that pose ethical dilemmas requiring more than simple solutions, including Bertram's forced marriage and his ambiguous conversion at the end.
Shakespeare based the play on the tale of Giletta di Narbona, which is tale nine of day three in Boccaccio's The Decameron. F. E. Halliday speculated that Shakespeare may have encountered the tale through William Painter's Palace of Pleasure, a French translation of the source, rather than reading Boccaccio directly.
Peggy Ashcroft played the Countess in Trevor Nunn's Stratford production in 1982, delivering what critics described as a performance of "entrancing...worldly wisdom and compassion." Judi Dench is among others who have taken the role. In the BBC Television Shakespeare production, Celia Johnson played the Countess dressed to evoke Rembrandt's portrait of Margaretha de Geer.
The 1741 production at Drury Lane was beset with misfortune. The actor William Milward, playing the King, fell ill and delayed the opening until the 22nd of January. On the first night, Peg Woffington, playing Helena, fainted and her lines were read by a stand-in. Milward fell ill again on the 2nd of February and died on the 6th, giving the play an "unlucky" reputation similar to that of Macbeth.