Avalyn Hunter has a series of articles on declining thoroughbred sire lines ("Lines in the Sand") in The Blood Horse. The first part featured the the Matchem/Fair Play/In Reality, Domnio, and Plaudit sire lines. No link so you must buy the magazine. (I would not recommend her new book on Northern Dancer, "The Kingmaker", unless you are real pedigree junkie)

Other interesting pedigree reads

History of the Leading Sires in North America by John P. Sparkman

The Pedigree Guru
 
Drawing the Lines by Rommy Faversham