The Meaning Of Liff was a very popular little paperback when it came out in 1983.

It was, as John Lloyd, is quick to admit, a very simple if slightly oblique idea. The aim of its authors, Lloyd and Douglas Adams, who had worked together on the first series of popular radio series The Hitchhiker's Guide To The Galaxy, was to produce a thesaurus of words for things that are in need of one, by re-purposing (an expression that was not yet in common usage) the names of places.

Lloyd illustrates the technique at regular intervals through his first Fringe show in nearly 40 years, Liff Of QI, which is enjoying a sold-out run at Underbelly's Dairy Room, but those examples should be left for the show. When the book came out, however, its authors invited submissions from fans for a follow-up. These were mine: Portrush - to walk as quickly as possible so that the person you don't want to talk to doesn't catch up; and Inverkeithing - to dawdle to avoid gaining on the person ahead of you for the same reason.

When we speak, Lloyd claims to recall our meeting in the Grosvenor Hotel, Glasgow, when he and Adams were on the original book's promotional tour, which may or may not be true, but is charming of him.

He is, though, a charming man, which might seem unlikely given his history of involvement in some of the most inventively acerbic and satirical broadcasting.

He was in at the birth of The News Quiz and co-created Not The Nine O'Clock News, which has been undergoing a timely re-evaluation in the wake of the death of Mel Smith.

His name is also on the list for Blackadder and Spitting Image. These days he and his wife Sarah head the company that makes his latest clever idea, the Stephen Fry and Alan Davies-starring QI.

All of this, and more, is contained in the show with the portmanteau title, Liff Of QI, a self-penned trawl through his achievements that boasts more of the talent of others, but ensures that whatever your own "in" to the life of Lloyd - from his youthful friendship with Adams to the current success of QI - you won't leave disappointed. As he says, it is neither a lecture, nor stand-up, nor a play, but it is really Quite Interesting, and rather charming.

"I have only really ever had one idea, which was to look at things that are boring and try to make them interesting. If you pay close attention to detail, boring subjects can be made interesting. You pick the nuggets out of the rubble," he says.

"That's why I have always thought comedy that has no ideas in it is just the silly joker in the pub. Good comics have their own way of looking at the world."

Lloyd's return to the Fringe is in part to promote a new book that is published next week (but available to audience members) called Afterliff, which takes the practice honed in The Meaning Of Liff and extends it into some concepts and phenomena of modern life that currently lack a method of succinct expression. It has been written with Jon Canter, another old friend of Douglas Adams and a novelist and scriptwriter.

When Lloyd last appeared on the Fringe, however, it was with Adams himself and David Renwick, who wrote One Foot In The Grave and Jonathan Creek, as Cambridge students in a 1976 review called The Unpleasantness At Brodie's Close - a title adapting that of a Dorothy L Sayers Lord Peter Wimsey thriller to their Royal Mile location.

Lloyd is understandably wistful about those days when the Fringe seemed a more manageable, and less professional, operation, and the trio put out their own chairs and sold their own tickets from a card table in the close and changed costume in a window alcove behind a curtain.

"The whole experience was hilarious and we did well. We made enough money to give each of us £5 at the end of the run."

Liff Of QI is at Underbelly at 4.40pm to August 24, when an extra performance has been added at 11.50am. Afterliff is published by Faber on Thursday.