Don Quixote (in full, Don Quixote de la Mancha) was a 17th century Terran novel by Miguel de Cervantes, as well as the name of its main character, a mad farmer in Spain turned would-be knight-errant.
Don Quixote was a favorite book of James T. Kirk, and he gave it as a gift to King Stevvin of the Shaddan. Stevvin also enjoyed the book, and wished he could have met the author that had created such a dreamer. (TOS novel: The Covenant of the Crown)
Don Quixote was also a favorite book of Cervantes Quinn. He apparently named his Mancharan starhopper Rocinante for Quixote's horse, and when he obtained Zett Nilric's argosy, he renamed it Dulcinea, after Quixote's love interest. (VAN novel: Precipice)
In 2367, Geordi La Forge, Data, Deanna Troi and Guinan ran a holodeck program of the adventures of Quixote and his companion Sancho Panza. (TNG novel: Vendetta)
The phrase "tilting at windmills," meaning to fight futile battles or imagined enemies, originated from this novel. (NF novel: After the Fall; TNG novel: Losing the Peace)
David Mack notes in his annotations for his VAN novel: Harbinger that the name of Cervantes Quinn and of the Mancharan starhopper are also nods to Don Quixote and its author.