Alexander Mellis Thompson was born at 14 South Mount Street in Aberdeen¹, Scotland on 19 October 1875.

He was the son of Adam Howie Thompson (b. 23 May 1847 in Ordiquhill, Banffshire), a stonemason, and Isabella Mellis (1850-1921, of Cairney, Aberdeenshire) who had married in Cairney on 31 December 1874. He had two siblings: Edwin (b. 1885) and Adam Howie (b. 1892). Thompson’s family later ran the Seaview Hotel in Peterhead, Aberdeenshire.

Alexander first appears on the 1881 census as a visitor to the home of his widowed maternal grandfather Alexander Mellis (b. 1820), a crofter of five acres in Ruthven, Cairney; his father was listed elsewhere as a boarder at 53 Green Street in Aberdeen. The family were living in Boddam, Peterhead, Aberdeenshire by the time of the 1891 census. 

Alexander would be absent from the family home at the time of the 1901 census, then the Seaview Hotel and he was listed elsewhere as a boarder at 2 Waters Close, Leith, Midlothian and was described as an unmarried mason; he specialised in letter cutting.

He was married in Boddam in 1902 to Isabella Dalgarno May (b. 13 June 1881 in Peterhead) and they later migrated to Woodstock in Cape Town, South Africa where Alex, among his other works, inscribed a plaque at the summit of Table Mountain. 

Alexander and Isabella had three children: daughter Isabella was born in 1905 whilst they were in South Africa; following their return to Boddam they had two sons, George Alexander (1907-1979) and Adam (1911-1941). 

The family appear on the 1911 census living at 4 Stirling Village, Boddam, Peterhead; their next door neighbours were his wife's widowed mother and her daughters. Thompson was described as a monumental stonemason and he worked as a stone polisher in Boddam Granite Polishing Works. Having had previous experience of working in South Africa and, reportedly America, Thompson and his family made plans to settle in Barre, Vermont and he was travel ahead first where it appears he had secured similar work, to be joined by his wife and children at a later date. 

Thompson, who had just been admitted as a Freemason, was originally supposed to have travelled aboard Cymric, but the cancellation of that ship's crossing due to the coal strikes altered his plans. He boarded the Titanic at Southampton as a third class passenger (ticket number 32302 which cost £8, 1s) and was destined for Barre, Vermont. Whilst aboard he sent a postcard to his wife which was posted in Queenstown on 11 April 1912:

Dear Lib.

Getting on all right, after leaving Sthampton (sic) we sent to Cherbourg France and we are nearing Queenstown. It is very comfortable here and as steady as a rock, but the feather beds are a bit hard.

Kindest love to all,

Alick.

Alexander Thompson lost his life in the disaster and his body, if recovered, was never identified.

A BODDAM PASSENGER
Amongst the passengers on board the Titanic was Alexander Thomson (sic), belonging to Boddam, a son of Mrs Thomson, of the Seaview Hotel there. Mr Thomson was a young married man, engaged as a stone polisher in the Boddam Granite Polishing Works, and was on his way to Barre, Vermont, to enter on the same occupation. He had experience of previous work in America and also in Africa, and was known as a deft and artistic workman in lettering and designing. His mother, his wife, and his three children are resident in Boddam, and much concern is being expressed. Mr Thomson was made a Freemason just before sailing...
— Buchan Observer and East Aberdeen Advertiser, 23 April 1912

His brother Adam later served with the Gordon Highlanders during WWI and was in training with the RAF when he was killed in a plane crash on 7 September 1918 aged 26.

Thompson’s widow Isabella did not remarry and remained living in Aberdeen; a late resident of Bonnymuir Place, she died on 21 May 1956 at the age of 74. 

His eldest child, daughter Isabella, is believed to have later married but details about her later life are not certain.
His youngest son Adam, who never married, later worked in the merchant fleet and was Junior 4th Engineer aboard SS Almeda Star when that ship was repeatedly attacked and eventually sunk on 17 January 1941 whilst en route to Buenos Aires. There were no survivors from the sinking. 

His son George worked as a Post Office (telephone) engineer from 1936 and was married in 1938 to Maud Isabella Mitchell, with whom he raised a family. He remained a resident of Aberdeen, retired in December 1970 and died on 15 June 1979.

The postcard Thompson had sent to his wife was discovered years later by family and auctioned by Sotheby's in 2002 for in excess of £7000.