by Henry Cornelius Agrippa : A 15th-century encyclopedia that synthesized various magical systems and laid the groundwork for modern Western magic.
by Dion Fortune : A classic manual focused on detection and defense against "psychic attacks" and negative energies. Occult Ebooks
For those looking to start a practice, these modern ebooks offer more accessible entry points: by Henry Cornelius Agrippa : A 15th-century encyclopedia
These works are considered essential for building a serious occult library and are widely available in ebook format: Occult Ebooks
by Israel Regardie : A comprehensive account of the teachings and ceremonies of the Hermetic Order of the Golden Dawn, though it is noted as being quite dense for absolute beginners.