Legends of the Rosemary Amp

A story about Marshall's legendary line of guitar amplifiers and a gumshoe detective story about the mythology of “Rosemary”. Who is Rosemary and why are her amps so special? Considering that the 1970s Marshall amps are among the most influential pieces of gear from one of the most influential and male-dominated periods in Rock music history, what can we make of the legacy of these skillful ladies?