Sporting clay shooters are constantly striving for consistency. Move, Mount, Shoot describes the maintained lead method, an easily learned technique. which will help both novice and expert alike achieve spectacular results.
This guy was remarkable as the O.G. of move mount shoot - a popular phrase that other techniques have latched onto.
This seminal work has been obsoleted by some better resources out there. The same material is better organized and expressed elsewhere; and in much more detail. Treatment of hold and focal points is light. I would recommend the Ashes' "If it ain't broke" over this one.
Some key points from the book: Maintained lead requires less timing than other techniques that don't match barrel to bird speed. Keep barrel below the bird and come up from below. Take the shot as soon as the gun is mounted. Swing from the hips. Give yourself extra swing room for insurance. The lead at the muzzle is the same for a bird at a given trajectory in relation to the shooter no matter what the distance (ignoring friction :)).