Marginalia

ᶠʳᵒᵐ ᵈᵃᵛⁱᵈ ᶠᵒˢᵗᵉʳ ʷᵃˡˡᵃᶜᵉ’ˢ ᵗᵉᵃᶜʰⁱⁿᵍ ᶜᵒᵖʸ ᵒᶠ “ᵗʰᵉ ˢⁱˡᵉⁿᶜᵉ ᵒᶠ ᵗʰᵉ ˡᵃᵐᵇˢ.”

Books (and other written works) are notoriously one-sided. The author gives and the reader receives. It can be difficult to stay active as a reader, especially if the material is difficult or unfamiliar.

Marginalia (or margin notes) are your conversation with the writer. Summarize their ideas to check understanding. If you don't understand or agree with what you read, write down why. Ask questions. Expect good authors to answer them later.

If you read the book a second time, your past margin notes will have the effect of allowing you a conversation with your past self. If you pass the book on to someone else, you will be adding someone knew to the conversation.

Underlines

Sidelines

Margin codes

The Marginal Obsession with Marginalia