I'm a fan of The Saragossa Manuscript by Jan Potocki and (inspired by it) am interested in running a role playing game set primarily in early modern Spain. I would like to achieve some level of historical verisimilitude in the campaign. What books (or other media) would /r/AskHistorians suggest, especially with an eye toward political intrigue and period beliefs on the fantastic or supernatural?
Considering the inspiration for the campaign, I welcome suggestions for both non-fiction and fiction titles.
J. H. Elliott's Imperial Spain: 1469-1716 is one of the benchmark texts on early modern Spain. I would also consult Geoffrey Parker's The Army of Flanders and the Spanish Road, 1567-1659: The Logistics of Spanish Victory and Defeat in the Low Countries' Wars is an excellent book that covers details of Imperial Spain's long logistical tail, which could be quite useful for a campaign. Early Modern Spain: A Documentary History edited by Jon Cowans is a collection of primary sources from Spain and could aid the narrative.
Adding to /u/kieslowskifan 's fantastic recommendations, Geoffrey Parker's book "The Grand Strategy of Philip II" will be a great resource for you as it covers quite a bit Philip II's daily life and that of his staff. Beyond that, "Danubia" can be a good source of inspiration even if 1) it is strictly speaking not a history book and 2) it is primarily about the Austrian Habsburgs; however the Spanish were heavily invested in the EYW and TYW so it gives a useful image of Spanish (Havsburg) life in the early modern era.
There is some fantastic music from Spain in the Renaissance as well, all of it public domain (obviously) so it can be used however you like. I recommend Cabezon (Diferencias sobre el canto del caballero, dif. sobre la pavana italiana, dif. sobre guardame las vacas--these are three pieces by the way), any set of variations on La Folia/La Follia (depending on the composers spelling--it's an ancient spanish melody, one of the earliest we know).
Other good composers are Aguilera de Heredia, Francisco Guerrero, and Tomas Luis de Victoria, who wrote a setting of "O Magnum Mysterium" which is still enormously popular with choirs today.
About fiction books, you should check some of the main works of the picaresque genre like "Lazarillo de Tormes", Mateo Alemán's "Guzmán de Alfarache" or Quevedo. Also, check Quevedo's life for some political intrigues. There is little supernatural events in these books and they are usually centered around lowlifes, not what you may be looking for but they are a good portrait of some Spanish social issues and character traits. Maybe the mystic poems of Santa Teresa, too, or de Roja's "La Celestina". "Fuenteovejuna" from Lope de Vega or Luis Vélez de Guevara's "El diablo Cojuelo". More in this wiki article: https://es.wikipedia.org/wiki/Siglo_de_Oro#Literatura
If you want something more supernatural I think you should search more modern books, maybe 19th century romanticism or gothic literature. Check Bécquer's "Rimas y leyendas", with some kind of gothic fantasy tales. I also remember Blanco White's "Letters from Spain", it's from the 18th century but it has some really interesting descriptions of old Easter traditions, like the Oficio de Tinieblas and another tales of naughty nuns, a staple in Spanish literature :)
In a more Potocki's vibe, check "Urban Magic in Early Modern Spain: Abracadabra Omnipotens" by María Tausiet, with lots of first hand tales and testimonies from people accused of witchcraft and Julio Caro Baroja's book about witches. Can you read Spanish? If so: http://es.scribd.com/doc/116059399/Hechiceros-y-brujas-en-la-literatura-espanola-del-Siglo-de-Oro
Of course, watch the "Manuscript found in Saragossa" film, is just wonderful