That's worth a read.
My dad was friends with Sedge and I have a lot of respect for what he did--at the time is was amazing. Conceptually, a lot of it is just as valid today as when he did the work, but some of his indicators are no-longer effective measures. I've yet to be able to find anything that the "Coppock Curve" does any more that other things aren't doing as well or better. The one thing I would NOT use it for is top-picking.
Mark