What is the major way for a lawyer to learn law?

The law is a great mass of rules, showing when and how far a man is liable to be punished, or to be made to hand over money or property to his neighbors, and so forth. These rules are contained in books. A lawyer learns them mainly by reading books.
   He begins by doing little else than reading, and after he has prepared himself by, say, three years’ study to practice, still, all his life long and almost every day, he will be looking into books to read a little more than he already knows about some new questions which he has to answer.
   The power to use books, then, is a talent that a good lawyer ought to possess. He ought to have enough ability to make it easy for him to collect ideas from printed words. He ought to have some readiness in finding what a book contains, and something of a sense for where to look for what he wants.
   But although this is the power of which he will first feel the need, it is not the most important. A lawyer does not study law to recite it; he studies it to use it and act upon the rules which he has learned in real life. His business is to try cases in court and to advise men what to do in order to keep or get out of trouble. He studies his books in order to advise and to try his cases in the right way.