I think the answer to both is the same. Yes, but...
I am new to bird keeping, having gotten my first birds nine months ago. But I've been on the 'net for just about a year learning all that I could, and I've learned a lot for which I am truly grateful (and my birds are, too).

But yesterday I got The Finch ... a Breeders' Companion and boy, my eyes are ready to be opened. For example, if you'd asked me, based on what I've learned on the 'net, I would have said that there is one disease that humans can catch from birds, Chlamydiosis. But Breeders lists 6, plus mites. It also gives human symptoms for these diseases as well as precautionary measures.
In the giving of medications administered in the water the book gives 15 warnings, for example Avoid medicating birds in the drinking water during very hot or rainy days, as they may consume too much or not enough of the medication.
These are things I've learned in just browsing through the book, and am excited about what else I will learn.
Don't get me wrong. I greatly value what can be learned on the 'net, especially a forum like this that allows novices like me to get advice to specific questions/concerns from those that have perhaps decades of experience in finch keeping. I think it is priceless. But I think it's complimentary to, and not a substitute for an authoritative, comprehensive book.