Short answers, pulled from the story.
Don Quixote Part One was published on the 16th of January 1605, after Cervantes sold the rights to publisher-bookseller Francisco de Robles in July 1604. Part Two, the genuine sequel, appeared in 1615, a year before Cervantes died.
Don Quixote was written by Miguel de Cervantes. It follows Alonso Quijano, a minor nobleman from La Mancha who reads so many chivalric romances that he renames himself Don Quixote, recruits a farm labourer named Sancho Panza as his squire, and sets out to revive chivalry as a knight-errant.
Don Quixote is considered the first modern novel because it moved beyond the episodic disconnected structure of medieval romance and explored the psychological evolution of its characters. Harold Bloom described its protagonist as a figure at war with what Freud called the reality principle. In 2002, writers from 55 countries surveyed by the Norwegian Nobel Institute voted it the greatest work of fiction ever written.
Tilting at windmills means attacking imaginary enemies or pursuing idealistic goals based on misperceived adversaries. The phrase comes from a scene in Don Quixote in which the protagonist mistakes windmills for ferocious giants and charges at them on horseback; the word tilt refers to jousting.
A spurious Part Two was published in Tarragona in around September 1614 under the name Alonso Fernández de Avellaneda of Tordesillas. The real author was never identified but was believed to be an Aragonese admirer of Lope de Vega, Cervantes's rival. The fake's prologue insulted Cervantes directly, and Cervantes incorporated the counterfeit work into his own genuine Part Two, published in 1615.
Don Quixote is believed to have sold more than 500 million copies worldwide. It is also one of the most-translated books in the world, with the Cervantes Collection at the State Library of New South Wales holding over 1,100 editions, assembled by Ben Haneman over thirty years.