This is the title of a new ebook by Peter Hayes and Don Stazicker based upon their detailed photo and video observations over several years in the UK and elsewhere.
It is fascinating and the best resource on river trout fishing that I have come across by a long way. The authors are very pleased to debunk commonly held perceptions and can evidence their stance by fabulous freeze-frame photographs taken in or above the river. There are hyperlinks to the videos that are most easily accessed by a single click from PC or Mac rather than on a tablet.
A scholarly but very digestible work and cracking value at less than a tenner!