This is the one that started it. A short rhyming declaration from a parent to a child, one spread at a time, with die cut cuddle bugs punched through the board so a baby can push a finger through and find the next page waiting.

What makes it survive the fiftieth reading is that it is written to be said rather than recited. The lines are short, the rhythm is steady, and the illustration by Natalie Marshall keeps to a few strong colours so a very young eye can actually track it.

It is 18 thick pages at seven and a half inches square, sturdy enough to be chewed, dropped and carried around by one corner. Silver Dolphin's You're My Little series has passed 4.1 million copies sold, and this is the title people keep coming back for when a friend has a new baby. Publisher guidance is 0 to 2 years, which is exactly when a child wants the same book every night.