I've owned the PPS book for more than 10 years and I'd rate it a very good book.
Curtis Arnold's core pattern is the symmetrical triangle. These are good patterns to trade and are very profitable when traded in the direction of the trend.
The limitations of symmetrical triangles are.......
1... They don't occur all that often in each stock (although you get quite a few if you follow enough stocks)
2... They're difficult to scan for....a distinct disadvantage if you're trying to find them among a large number of stocks.
3....They mostly occur after the trend has been under way for some time. Usually there are various other patterns that would have given you a far more timely entry than the symmetrical triangle.
In the PBG chart, for example, long before the triangle showed up there were various other patterns that would have put you into the downtrend and had you harvesting good dollars on the short side. This does not in any way detract from the validity of the triangle as an entry signal when it eventually showed up.
Another good pattern outlined by Curtis is double tops and double bottoms. What's interesting is that he uses them as trend continuation patterns, not trend reversal patterns.
We've all seen someone give examples of a double top calling the end of an uptrend, and giving a signal to go short once price falls below the trough between the two tops.
And we seen examples of double bottoms calling the end of a downtrend, and giving a signal to go long once price climbs above the peak between the two bottoms.
Curtis did extensive testing that showed double tops/bottoms to be unreliable when used in this manner. Instead, he looks for double bottoms that occur during uptrends, and double tops that occur during downtrends.
Example......
A stock or market is uptrending, then starts selling off....a counter-trend retracement. After a few days the selloff ends and the uptrend resumes, creating a trough within the uptrend.
Several days or maybe a week or two later, another selloff. This second retracement goes to the same or very similar level as the first retracement, then the uptrend resumes.
Now you have a double bottom within an uptrend.....a valid buy signal.
The mirror image of this pattern is a double top occuring during a downtrend. A downtrending stock or market rallies temporarily before resuming it's downtrend. A bit further down the track, along comes another temporary rallies that ends at the same or similar level as the first rally. Now you have a double top within a downtrend...a valid short entry signal.
I've found this pattern to be fairly rare, but when it shows up I'll trade it without hesitation, due to it's reliability.