TL;DR means ‘too long; didn’t read’. It began as a put-down and became a courtesy.

The phrase has two uses: a reader can reply ‘TL;DR’ to a long post, or a writer can place ‘TL;DR:’ at the top or bottom with a summary; the writer makes the cut for the reader.

I love it. I have always sought simplicity on the far side of complexity (Oliver Wendell Holmes).

Early in my career, and partly by accident, I cut a two-day training course to one day, and it became more effective. My boss was pleased, and I was astonished. I became hooked on the idea that less is often more. My pioneering Personal Excellence course, which ran worldwide, gave attendees a focused approach to turning their lives around in just two high-value days; it regularly amazed people with what we achieved through great structure, powerful exercises and, if I may say so, good teaching.

Ancestors Th expression TL;DR is young, but the impulse is old. The best-known ancestor is Blaise Pascal’s apology in his Provincial Letters (1657): he wrote that he made the letter longer than usual only because he didn’t have time to make it shorter; I remember an English teacher introducing us to that idea, and it was an epiphany.

The observation makes TL;DR interesting rather than lazy; it takes more work than length, and a good TL;DR shows the writer did that work. One of my books, How to Be Brilliant, was (deliberately) very short. An early Amazon critic complained, ‘£10 for that!’ Fortunately, all other reviewers understood that they were paying for the work of powerful brevity.

Other approaches include the scientific abstract, the newspaper’s inverted pyramid (the most important facts first, with details lower down), the executive summary and the telegram, where every word cost money.

The ancient world valued the same thing. The Spartans were so well known for short replies that the word laconic comes from Laconia, their home region. Philip II of Macedon, father of Alexander the Great, sent the Spartans a threatening message: If I invade Laconia, you will be destroyed and never rise again. The Spartans replied: If.