Nueva gramatica folletito by the Real Academía Española. PDF with historical detail. Free download
From Amazon: Nueva Gramática de la Lengua Espanola (Manual) (2010) 1080 densely packed pages US$12.20. The “manual” grammar is a shortened version of the full Nueva gramática de la Lengua Espanola (Real Academia Española y Asociación de Academias de la Lengua Española, 2010; 4032 pages; US$175); and while this is not available for preview, you can download a searchable PDF of the chapter on gender here.
A History of the Spanish Language, Ralph Perry (google books–searchable with limited preview)
First Spanish Reader: A Beginner’s Dual-Language Book (Beginners’ Guides) by Angel Flores. Review at Goodreads: “This small book of barely over 100 pages includes parables, folktales, and short stories from Spanish writers in a dual language format, with Spanish on one page and English facing it.”
Spanish-singing musicians: Juanes, Tiziano Ferro, Thalia, Shakira…