“In a nutshell” is an idiom which describes summing something up in a concise way, or “in a few words.” For example, “Just give me the facts in a nutshell.”
Shakespeare’s Hamlet used it when he said, “I could be bounded in a nutshell, and count myself a king of infinite space, were it not that I have bad dreams.”
The phrase originated in an ancient story, told by the Roman scholar, Pliny the Elder, in CE 77. The story went as follows: the great philosopher Cicero witnessed a copy of Homer’s epic poem The Iliad written on a piece of parchment that was small enough to fit into the shell of a walnut.
Pliny’s words were translated into English in 1601 by Philemon Holland, who included this explanatory note: “We find in Histories almost incredible examples of sharpness of the eyes. Cicero hath recorded, that the poem of Homer called The Iliad, written on parchment, was enclosed within a nutshell. The same writer maketh mention of one who could see to the distance of 135 Miles.”
I find that impossible to believe. The Iliad is about 700 pages long and, in Homer’s day, would have been written on clay tablets. But it makes a nice story.
The use of “in a nutshell” to mean specifically “in few concise words” didn’t begin until the 1800s. Thackeray used it in print in The Second Funeral of Napoleon, 1841.
Getting the information you need in a concise form, without all the superfluous waffle is a good thing.
And that’s “in a nutshell” in a nutshell.