Cockatiels - parrot-related birds that originated in Australia - come in a variety of color mutations. This handbook gives detailed purchase advice, considerations related to caging, proper nutrition, grooming, health care, and keeping the bird safe from household hazards.
A must have book for cockatiel owners such as myself. I enjoyed the section about nutrition / feeding the most; extremely detailed. Also includes at the end of a book extensive graphs/formulas, etc for breeders, which is not my huckleberry, but I appreciated the amount of detail.
Another important factor covered are cockatiel illnesses and how to spot them before they become fatalities. Much more informative than the average "quick peek" fliers out there from vets, although those are usually good too.
My opinion is, whatever material is out there at your local library, Amazon, or wherever ... read it. All have a bit of something to offer the other may not. Our companion birds depend on us entirely for their health and happiness since they are basically given little choice in who owns them.