On this day 17 years ago, I sat was sitting in the living room of our house in Sanda. I had just finished teaching the evening's English classes, the students had left, I had cracked open a can of Asahi and flopped on the sofa. I switched on CNN only to see a tall building on fire and watched as, a few minutes later, an airliner crashed directly into its twin. And so began a decade and a half of war, which continues in Afghanistan and Syria today.

Everyone will know the event I am talking about and it requires no more commentary, since it has been gone over and over and over. I would never seek to minimise the significance of those events, which reverberate into the present and have cost dearly.

It is September 11, 2007, that exercises my keyboard today. On that day a long time friend, Robert Mumford, left his Defence Department job in Sydney, caught a train to Newcastle and, with the exception of a brief hotel lobby video and some alleged sightings, was never seen again. I didn't know at the time, in fact, not until I saw a program on missing persons. He had disappeared without cause and the matter remained a mystery to us all until his remains were discovered back in the Blue Mountains, in bushland, a few years later.

I have written about Robert before. He was one of those "one-offs", an eccentric man who was very smart but whose gifts were never fully realised. His serious lack of confidence in himself and low self-esteem did not help, in fact, they made him an easy target for the less gifted and more mendacious. He was the doyen of many pub trivia nights, took part in comedy performances (though his material lacked popular appeal), drove hundreds of kilometres for no reason and could perform the most bizarre calculations. I can't remember how many F4 Phantom jets it would take, nose to tail, to reach from the Earth to the Moon, but Robert had done the maths and knew the answer. He had an almost eidetic capacity for detail, especially concerning his abiding passion, The Beach Boys.

I lived for a short time in a share house with Robert and there was rarely a day when a Beach Boys related tune was not wafting from his bed room. Not just songs from actual albums, but bootleg tracks, backing tracks and session outtakes. For the time (1983) it was a seriously deep collection that went well beyond the record shop and into some kind of Brian Wilson Master Vault. Robert had an ongoing obsession with Wilson and he would often tell me about his troubled life - his creativity, fall from sanity, life in a sandpit and so forth. I heard so much about the man and then so repeatedly that I feared he would enter my dreams and cause a breakdown by association.

Above all, Robert was a kind and gentle man who spoke well of everyone. He could have you in stitches or he could overstep his welcome, for he did not always read people well. But this morning, when I remembered the date as I made my way down a bush track descending to Lake Woodford, I wished that he was walking alongside me.