Getting licensed gives you a chance to practice your skills before you need them. While the books cover the topics, learning to be a radio operator requires actual practice.
Many upcoming exams are listed on the ARRL site. Some clubs offer exams that aren’t posted, so check in your area. At the test session, you’ll need to have a photo ID, your SSN or FRN, and an address that will appear in the public database. It doesn’t have to be your home address, but the FCC requires some way to contact you.
The ARRL and others publish books that contain all you need to pass the exam, including the current question pool with answers, along with other useful information and tools. The information in older editions will be useful, but the questions change every several years and you’ll need to go online to see the new questions. There is a book for each license level.
Online study without a book is also possible: there are flash cards, practice exams, and other resources.
Practice Exams and Flash Cards:
The flash cards review all the questions, not just give you a set of 35 (or 50 for Extra license) to simulate the test. Some questions are obvious enough that just seeing the correct answer will give you aedquate information. When you select an answer or click “I don’t know”, there’s a little folded corner (upper right) to click on to give you an explanation plus links for more info. They also have practice exams, but I prefer other interfaces. This site does not show exam scores until the end.
This also has practice exams with scores at the end, but a better interface, I think, and it gives you the question pool number (can be helpful to some people). They also have flash cards, but not with detailed info.
http://aa9pw.com/ Similar to above. (select exams on left side)
This practice exam gives you the answer immediately as you go along.
Study guides and books
Study guides focus on the test questions, unlike the main ARRL book and others which include related information that won’t be on the exam. Here’s one example of a study guide (not a personal recommendation; I didn’t use one):
http://www.kb6nu.com/wp-content/uploads/2015/03/2014-no-nonsense-tech-study-guide-v20.pdf It’s free there, but sold elsewhere.
ARRL publishes a “Q&A” series of books (one for each license level) that focus on the exam questions. http://www.arrl.org/studying-for-a-technician-license
Another popular series of detailed study materials: The Gordon West Radio School http://www.gordonwestradioschool.com/main/page_w5yi_training_resources.html
The General exam covers much of the same material and will be offered to you for free (usually) if you pass the Technician exam. It could be worth the effort to study both and end up getting more operating privileges right away. The Extra license material is much more difficult for most people.
To get more info on almost any radio topic, just pop it into a search engine and add the words “amateur radio” or “ham” to get something geared toward the radio operator. Many of the concepts will be covered in other disciplines (like physics or general electronics), so you’ll want to narrow the search.