MAPS

Match Making: A Striking Industry in Letchworth

Marriages

Medicinal Waters: The Physic Well, Barnet

Memorials  (also In Memorium cards)

Mental Health: ASYLUMS

Military

Militia Lists and also Hertfordshire Militia Ballot Lists

Milk: Skimmed Milk in  St Albans

Mirror Writing - see Hidden messages on post cards

Monumental Brasses: Hertfordshire Brasses;  Lord Verney, Aldbury

Motor Cars

Murder: The Murder of Edward Anstee in 1880,  Who's Who for the Marshalswick Murder [word file]