If you use technical analysis in your trading, you owe it to yourself to study Mark Lim's The Handbook of Technical Analysis (Wiley, 2016). It's a hefty book, nearly 1,000 pages (which, for some strange reason, is not available in hard cover, only in paperback or in a digital edition). You certainly won't read it straight through in a couple of sittings. But it is a treasure trove of information and often subtly different interpretation, not simply a rehash of all the other books on technical analysis that are available. It is also, as the cover says, a suitable text for those studying for certification as a technical analyst in the U.S., U.K., or Australia.
The book could have used a good proofreader, but otherwise, it is a first-rate self-study guide and reference book. Those who buy the book also have access to an online test bank.