Notebook is a style of writing where people jot down what they have thought or heard at the spur of moment. The contents of a notebook are unorganized, and the number of subjects covered in a notebook are unlimited: a paragraph of autobiography can be followed immediately by one on astronomy or one on history.
Some famous authors are also famous for the notebooks they left. The Italian poet Giacomo Leopardi kept a notebook, called Zibaldone, from 1817 to 1832. The idea of keeping that, which contains no fewer than 4,526 pages, was possibly suggested by a priest who fled from the French Revolution and came to live in the poet's hometown. The priest suggested that "every literary man should have a written chaos such as this: notebook containing sottiseries, adrersa, excerpta, pugillares, commentaria... the store-house out of which fine literature of every kind may come, as the sun, moon, and stars issued out of chaos."
There are writers who earned their posthumous fame solely by their notebooks, such as the German scientist and humorous writer Georg Lichtenberg. He called his notebooks "waste book," using the English book-keeping term. He explains the purpose of his "waste book" in his notebook E:
Die Kaufleute haben ihr Waste book (Sudelbuch, Klitterbuch glaube ich im deutschen), darin tragen sie von Tag zu Tag alles ein was sie verkaufen und kaufen, alles durch einander ohne Ordnung, aus diesem wird es in das Journal getragen, wo alles mehr systematisch steht ... Dieses verdient von den Gelehrten nachgeahmt zu werden. Erst ein Buch worin ich alles einschreibe, so wie ich es sehe oder wie es mir meine Gedancken eingeben, alsdann kann dieses wieder in ein anderes getragen werden, wo die Materien mehr abgesondert und geordnet sind.
"Tradesmen have their 'waste book' (scrawl-book, composition book I think in German), in which they enter from day to day everything they buy and sell, everything all mixed up without any order to it, from there it is transferred to the day-book, where everything appears in more systematic fashion ... This deserves to be imitated by scholars. First a book where I write down everything as I see it or as my thoughts put it before me, later this can be transcribed into another, where the materials are more distinguished and ordered."
The notebooks of scientists, such as those of Michael Faraday and Charles Darwin, can reveal the development of their scientific theories. On the other hand, the notebooks used by scientists for recording their experiments are called lab notebooks.
The notebooks used by artists are usually referred to as sketchbooks, which may contain more than sketches. Leonardo da Vinci's notebooks contain his writings on painting, sculpture, architecture, anatomy, mining, inventions and music, as well as his sketches, his grocery lists and the names of people who owed him money.
In Chinese literature, "notebook" or biji is a distinct genre, and has a broader meaning.