Arthur Douglas Guest was born on the Isle of Man in 1889, his younger brother Herbert was born 4 years later in 1893.  Their father was the manager of a boot and shoe store. The family later relocated to Leeds and Huddersfield in England.

On the 10th of February, 1908, Arthur enlisted into the Black Watch aged 18. Arthur's younger brother Herbert was 18 in 1911, and he too joined the Black Watch in late July/early August 1911. 
Why two brothers born and raised in the Isle of Man, then later grew up in northern England, chose to join a Scottish highland regiment is unknown.

Arthur was good at sports in the regiment, scoring the winning goal in a match against the Connaught Rangers to win the Irish Army Challenge Cup. It was reported he had the option of being bought out of the Army to play professionally for Huddersfield Town, which he declined.
He was also on the officers cricket team.

When war was declared in August, 1914, Arthur was already a Sergeant with the 1st battalion, having 6 and a half years service under his belt. Herbert was in the 2nd battalion out in India, where he was a Private 3 years into his service.

Arriving in France with the first cohort of the 1st Bn Black Watch, Arthur went through the long retreat of late August and early September. He then took part in the first attack carried out by the battalion, that of taking Sablonnieres on the 8th of September.
The next attack the Bn took part in was on the 14th of September on the Aisne. It was to be a day of hard fighting in open country that saw high casualties, including the Lt.Col who died of his wounds on the field.

At the end of September the Huddersfield Daily Examiner published a postcard Arthur wrote home to his parents:

"September 22nd, No. 4 General Hospital, Versailles, France.

Moved here yesterday, suffering from a slight wound. Am getting on nicely, and hope to be quite well again shortly. Have you heard from Bert lately? I don't think his battalion is out here yet. Hope things are well with all at home. Address as above.  I will notify you immediately I move from here.

Good luck,
Arthur."

Another letter from Arthur was published in mid October, this gave more detail on when and how he received his injuries:

"I got my wound on the 19th September, about the sixth day of the battle of the Aisne, which is still in progress.

We crossed the Aisne on the 12th, and camped that night near the river.
The next morning we marched up a hill, and instantly came under a heavy artillery fire. Our advance then lay across a number of level fields, affording but little cover. Gradually the fire became hotter, and machine guns and rifles began to "poop" at us.
A thick mist lay in front, and we could see nothing to fire at. A few hundred yards further and the volume of fire was terrible, shells and bullets dropping like rain. I quickly lost my officer, and then took charge of the platoon, about 50 men. We advanced by short rushes for about a half mile and then came to a road with a slight bank at the edge, which gave us a little cover.
Here we re-organised, and I had thirty-two men left. We again advanced, this time for about a mile, which took about three hours to cover, and we could not get more than fifteen or twenty yards at a time. We were ordered to halt here, and hold the ground we had gained, and this we did.

At night we again re-organised, and then entrenched. The enemy had retired about half a mile, and they were also "digging in," as we say.
When the roll was called we had only nine officers left out of twenty five, the remainder being killed, missing or wounded.
Our Colonel was killed, and my company commander Lord George Stewart Murray, wounded. I did not hear the number of casualties among the rank and file of the battalion, but in my own company we lost 78.
I seemed to bear a charmed life that day, and began to think I should never be hit, men continually dropping on my right and left the whole day.

We stayed in the trenches for six days after this, being shelled by heavy artillery (Jack Johnson's) from daybreak til sunset every day. One or twice they would send a few over during the night. and we would man the trenches expecting a night attack, but nothing happened until about midnight -19th- when they commenced a heavy bombardment. This continued for about an hour, when a few rifles commenced to send bullets whistling over. This was a night attack in earnest, and we immediately stood up and lined the trenches. It was a dark night, and we could see nothing.

While looking over the top of the trench a shell burst in front, and something hit me in the eye. It seemed like a blow from the sledgehammer, and down I went. When I came to about an hour after I found our chaps had beaten the enemy off, though the shells still came over. I had a bandage round my head, also a terrible aching. To improve matters rain started falling heavily, but I could not be moved til daybreak. I was then taken to the nearest field hospital, had my wound bathed and dressed, and then was moved by motor ambulance to another field hospital about ten miles away. I stayed there a day, and again motored some distance to a town, and from there came by rail to this hospital, the train journey taking thirty hours.

I believe this same battle still continues, even after about twenty seven days. I hope our boys are not in the same old trenches. Will tell you more of our doings when we are together again in Huddersfield."

Arthur had his right eye removed due to the damage caused in his wounding. He wrote home saying he regretted having to leave his regiment more than the loss of his eye. On leaving hospital he was provided with a new suit and artificial eye. Being discharged from the Army on the 12th of December, 1914, he received a pension of 17s 6d per week, for life.

Less than a month after receiving his discharge, he had secured an appointment, through the War Office, with the Inland Revenue in Edinburgh. When later offered a job at the Black Watch depot, he reluctantly declined, feeling this would prove too much of a strain on his remaining eye.

Herbert arrived at Marseilles with the 2nd Bn from India on the 12th of October. This was weeks after his brothers war and military career had come to an end with his wounding and hospitalisation.

Herbert served in France from the October until the 25th of September, 1915, when he was killed in action during the Loos attack.
Little is known of the near year Herbert spent at the front, however a letter to his parents notifying them of his death a month later states he was appointed a Lance-Corporal shortly before his death.

The letter is from Captain M. E. Raylin, of the 2nd Black Watch. It is much the same as many sent to bereaved family members. Doing their best to praise the ability of the deceased and how much they'll be missed by their friends in the army.

"Dear Mr Guest,

I am very sorry indeed to tell you that your son , No. 2124 Lance-corporal Herbert Guest, was killed in action on the morning of the 25th of September, during an exceedingly successful charge, in which the regiment completely broke the German line.

Your son had only just received the lance stripe, but I had already had every reason to be more than pleased at having recommended him for it. He was an N.C.O. of quite unusual promise, and had already shown himself a most useful and fearless soldier. He is a very great loss to the company."

A third brother, Sidney, joined the local territorial battalion, serving with the 5th Duke of Wellington's (West Riding Regiment) by early 1915. It doesn't appear that he served abroad.

In 1917 Arthur married Alice Millar and they had a son, Arthur Douglas jnr.
In early March, 1944, while still working for the Inland Revenue in Edinburgh, Arthur took his own life, aged 54 years.