One of the things I discovered when working on Rest was how commonly creative people keep a notebook handy, when going on walks, at their beside, or even by the pool. Tchaikovsky and Beethoven both carried paper and pencil on their long walks. Mathematician William Rowan Hamilton, Hamilton composer Lin-Manuel Miranda, director Billy Wilder, and molecular gastronomy pioneer Ferran Adrià all carried notebooks around when they were on their feet.

For most, it seems that this was a way of catching ideas while in motion that they otherwise lose. The physiologist Hans Selye carried a notebook to free his mind from the “information pollution” of small details and tasks and let him think about more serious subjects at “the limits of my tolerance.”

The other major time people need notebooks is in bed, to write down ideas that come to them as they’re falling asleep, or during dreams. It turns out that Charles Dodgson (better known as Lewis Carroll) has a unique system for dealing with this. As he wrote,

Any one who has tried, as I have often done, the process of getting out of bed at 2 a.m. in a winter night, lighting a candle, and recording some happy thought which would probably be otherwise forgotten, will agree with me it entails much discomfort.

Anyone who is familiar with the history of Oxford and Cambridge will know that the rooms could get ridiculously cold in the era before central heating and radiators. Even then, things could still be chilly: I had a high school English literature teacher (Miss Coleman) who would regale us with stories of how when she was at Oxford in the 1950s the heat in her room was coin-operated gas that ran out in the middle of the night, and she’d wake up freezing. But one can only imagine that in the late 1800s, unless you paid well for your coal, it was going to be cold.

As Stuart Dodgson Collingwood explains in The Life and Letters of Lewis Carroll,

At first he tried writing within oblongs cut out of cardboard, but the result was apt to be illegible. In 1891 he conceived the device of having a series of squares cut out in card, and inventing an alphabet, of which each letter was made of lines, which could be written along the edges of the squares, and dots, which could be marked at the corners. The thing worked well, and he named it the “Typhlograph,” but, at the suggestion of one of his brother-students, this was subsequently changed into ” Nyctograph.” [294-295]

Now, thanks to the nyctograph, Dodgson concluded,

All I have now to do, if I wake and think of something I wish to record, is to draw from under the pillow a small memorandum book containing my Nyctograph, write a few lines, or even a few pages, without even putting the hands outside the bed-clothes, replace the book, and go to sleep again.

The fact that Dodgson went to such lengths to devise a method that he could use in the middle of the night, in the dark, without getting out of bed, tells you something about how valuable these ideas could be, and how evanescent they are. It also suggests that while we think of a-ha moments or flashes of insight as rare and unusual things– Archimedes settling into the bathtub, that sort of thing– they actually are pretty common, once you know how to encourage and record them.