Books are good, yes.
But you can be trained in formal training for twenty years and never "get it", and you can go out your back door with no training or knowledge at all and just "get it". There is no guaranties, and none of it is where you actually get experience and wisdom. You get those from doing it.
If I went through the best medical school in the world, I wouldn't be able to go straight in and be able to do everything day one. As an example, I want into the emergency room for something. The doctor was concerned about something else because he hadn't ever seen it, but the nurse told him, no, that isn't normal, but it's not abnormal, and convince him not to worry about it. He had far more formal training than she did, but she had worked in the ER for many years and seen much more than he had. He had more knowledge, but she had more experience. In general, nurses see more and experience more because they handle most things that don't require the expertise the doctor has because of training, so have more wisdom to see things as they really are and know what to do in a lot more circumstances.
I read a quote in a book last night, Witches, Midwives, and Nurse: A History of Women Healers. "If a woman dare to cure without having studies she is a witch and must die." Note the emphasis on studying (indicating training, not reading, in this context). While the restriction of women in medical schools and the prevalence of women over men in folk practice was an issue at the time, it was more about credentials vs no credentials than about gender. The doctors felt only they should be able to heal because they were the ones with training, who had put in the time and effort to be trained, and could prove they were training. Not really different from today when the main argument against alternative medicine in the US is not about if it works or not, but about lack of a medical degree.
Back to the craft, same thing.
Training is good, and is required in some *traditions* to practice that *tradition*, for very good reasons, but is not required to practice the craft, and doesn't guaranty success in it, any more than reading books do. It's the experience that builds wisdom, and if you don't do anything until you have learned sufficiently to make no mistakes and always be good at it, you'll never reach that.
Read what you can, sure.
Get the formal, or informal, training if you can, sure.
But are real teachers are the spirits, our experiences, and our own self, seen through a mirror darkly.