For the following reason, I highly recommend The Encyclopedia of Chart Patterns by Thomas Bulkowski. If nothing else, it'll at least teach you to be cautious about placing too much reliance on T/A - because there's really no such thing as the perfect chart setup.
There is no chart setup, in other words, which will guarantee you money with more than an 80% chance of working at any given time. Bulkowski, having spent many years analysing all potential chart setups, focuses specifically in every instance on both confirmed and failed setups. It's surely important to study both sides of the T/A story, and it's no good being able to spot any pattern if you're unaware of its likelihood to fail. For example, the classic "double top" formation can have a failure rate of 65% - worse than tossing a coin!!! Albeit, Bulkowski advises, "double tops spaced close together have larger losses than those with peaks spaced farther apart". Too many books teach you just the patterns while glossing over the fact that they often do not work.
Ask yourself how worthwhile, in reality, with real money at risk, is your being well versed in chart patterns if you're going to be scratching your head wondering why your great setup nosedived, just when you went all in on the 'perfect chart' that you just read about last night?. Which is also why the above book should be in everyone's library.