Blimey. I'm just filling in a questionnaire for my publisher to help them with publicity for my new book. They ask me to list: "Books previously published (title, publisher, date of publication, cloth or paperback, ISBN, unit sales)". As it happens, when I wrote my MA thesis at Sheffield Hallam University — Subjectivity and Intersubjectivity in Human-Computer Interaction — the university asked me if they could publish it. I was flattered, and naturally agreed. It was sold for £4, though I got copies for £3.60. Whenever I got more of them (to give away), it always seemed that they had to blow the cobwebs off the box, and I was never aware of any publicity for the series in which the book ("monograph" we called it, pompously) was published. It was very low key, and it was 16 years ago.
Anyway, I know I have a copy of the book somewhere, but I doubt if I could find it. So, to track down the ISBN number I put the title into Google, and was stunned to find an Amazon listing showing the book as available. I'm almost sure it's not, but I'm very tempted to order a copy just to see. As for 'unit sales', ha, ha, ha! Never had a report of any kind from the publishers.