How can it be harder to write a "thank you" than to just say it? I guess because letters take more time, both to write and to read, and there is a permanent record of the communication in black and white, with no tone of voice or facial expressions for context.

You'll have gathered I found this one tricky, and not just because of my appallingly unpracticed penmanship...

The recipient was an easy choice, though. A lifetime ago at university, I had a professor who really believed in me. He encouraged my some-what unusual perspectives and interests, and always had time to talk things through and build my understanding. He had my thesis bound for me, because I couldn't afford that on my student budget, and gave sound guidance (even if I didn't always take it - still sorry about not taking that that internship and figuring out my transport issues). He also gave me the best career advice I ever had - the only person I can think of who didn't prevaricate with "you can do anything" but came right out with "you'd be great at this". And he was right; I'm finally doing the job he recommended all those years ago and I love it.

So I've posted a letter sharing my appreciation of the insights and support he gave me. Given how clearly I still remember his advice and support, appreciation feels like a bit of an understatement... His belief in me was, and remains, a challenge to live up to in my professional life; I want to be as good as he thought I was. It's been a long time, and it will probably feel like a bolt from the blue (I'm just hoping not too stalker-ish...), but Chris is right. It's right to let people know how much you appreciate it when they've had a profoundly positive effect on your life.