For those new to birding, it can be a challenge to figure out how to start learning, what books to get, and how to find the right optics. The information below should serve as a good starting point.
The National Audubon Society has some great resources on its website, including this article on how to start birding, and this very similarly titled article on the same subject.
Cornell's All About Birds website has this article with tips for beginning birders.
The American Birding Association's Code of Birding Ethics has long been the standard for responsibly birding. It is certainly worth reading and keeping in mind.
Binoculars are not strictly necessary to enjoy birding, but a good set can make a world of difference. Fortunately, optical quality has drastically improved in recent years, and excellent bincoculars can be found at many price points. The sheer number of options can be overwhelming. To help, Audubon has published this article discussing how to approach the decision, and this accompanying detailed guide to tested binoculars, with recommended models at several different price ranges. Bird Watcher's Digest's Optics Page has a lot of articles and reviews as well.
A spotting scope is definitely not necessary for a beginning birder, but if your addiction has taken root and you're ready, Audubon has again published an article discussing how to approach the decision, and a detailed guide to tested models with recommendations at different prices.
Bird photography is becoming more prevalent, with some birders eschewing binoculars altogether. As with binoculars and scopes, Audubon has come through, offering this page dedicated to photography, with tips on gear, technique, and photography ethics.
Optics models - particularly cameras - change very frequently, and the articles linked above won't be up-to-date for long. Get out in the field with other birders and ask to have a look through theirs (unless, of course, there's a global pandemic or something crazy). Most birders will be happy to let you try out their gear, and will share their thoughts on what they like and what they don't.
A good field guide is a necessity. Opinions on which field guide is best are varied and quite strong, but the following have solid arguments to be considered. In addition to the printed books, each has smartphone applications available for Andoid and iPhone. The phone apps have the added benefit of recordings of songs and calls for most species, among other functions.
The following books are great texts for those new to birding:
There are many more general field guides available, as well as specialized guides for groups of birds and types of birding. One great resource for finding bird books is Buteo Books, an online retailer of ornithology books and other media, and the outlet for the American Birding Association's book sales.