Homles & The Hat.

Every once in a while an illustration can be presented alongside the text and become iconic even though it is a narrative departure.
 The public view of the character Sherlock Holmes is inseparable not only with his friend, Watson, but also with his hat. The deerstalker. And yet Sir Arthur Conan Doyle never once described Holmes as wearing one throughout his series of novels. 
This depiction comes from the illustrations by Sidney Paget, originally published with the narrative in the Strand Magazine 1880's onwards. (It is of interest to note that as this is a 'countryside garment' the illustrator only showed Holmes wearing it in appropriate rural or travelling scenes and never in urban London.)

It is fascinating to see how such a narrative departure has produced one of the most iconic images of a character in fiction and perhaps without even having an illustration present in the text, changed the way in which we read it. The hat has been absorbed into our shared idiolect.

Sidney Paget

To quote the current BBC adaptaion: "It's not a deerstalker anymore, it's a Sherlock Holmes hat... you're this far from famous"