Distinguished American architect (1853-1906) who was a leading figure of the 'Beaux Arts' movement, best known for his opulent mansions and for the second Madison Square Garden. He was fatally shot and killed in the roof garden theatre of the Landmark by the husband of actress Evelyn Nesbit in retribution for a long-ago affair. ALS, four pages on two adjoining sheets, 4.25 x 6.5, March 6, 1896. Letter to the wife of sculptor Frederick MacMonnies, in part: "The sketches duly arrived and as I write Mac I am simply overpowered. I really melted with pleasure and continue to do so every time I look at them and I know the pleasure I felt on receiving them will mean more to you than any thanks, so I will not even attempt to thank you in words-But if you ever want a house built…you know where to come for it." Archivally double-matted and framed with a portrait of the architect to an overall size of 21 x 13.5, with a window in the backing for viewing the second and third pages. In fine condition.