Some methods described in these books are contradictory to each other. Some of the older publications carry outdated, albet interesting, material. Our understanding of aviculture is constantly growing and changing. Some books were informative and indispensable. Regardless of their content, each book imparted valuable information and insight into the facinating world of birds.
Parrots are wonderful companions.
Unless we are willing to educate ourselves, we risk the health and well being of these splendid creatures.