How to annotate a book: marks, margin notes and flags

Why annotate a book at all?

Annotation turns reading into a conversation. You stop at a sentence, say something back, and leave a trace you can find later. People have done this for centuries. Wikipedia's article on marginalia describes marks in the margins of a book, from scribbles and comments to glosses and critiques, going back to manuscripts.

The practical benefit is simple. A book with a few marks is searchable by hand. You can flip through it in ten minutes and rebuild the argument or the story. A book with no marks needs a full reread.

What should you write in the margin?

Brief reactions, not summaries. Write yes, no, why, compare to ch. 3, or a name for a pattern you spotted. A good margin note is something you could not recover from the text alone. If you are writing what the paragraph says, you are copying.

Leave the margins clear on pages that need no comment. A book where every page is covered in ink hides the pages that really mattered.

How do you annotate a library or borrowed book?

Do not mark it. Use removable sticky flags or a bookmark and keep your notes elsewhere. Thin flags stick out of the page edge without damaging the paper, and a color code tells you why you flagged a passage. A compact legend of four colors is plenty, and the guide to book tab colors suggests one.

When you finish, take the flags out one by one. Copy the lines you want to keep with their page numbers into a notebook or an app, then remove the flag before you return the book.

How do you annotate an e-book or an audiobook?

For e-books, use the built-in highlight and note features, and keep to the same code of colors. Export the highlights if the app allows it. For audiobooks, pause and use the bookmark function, then type a short note. A voice memo is faster, but a typed line is easier to search.

Highlights without notes are the easiest thing to collect and the easiest thing to ignore. Add one sentence in your own words to anything you want to remember.

Can you annotate on your iPhone?

Yes, with any notes app, and some reading apps add structure. Bookstub, an iPhone reading tracker in development, keeps lines: passages you type yourself, up to 280 characters, filed under a book, a page and a colored tab. The free legend has four tabs (Favorite line, Made me laugh, Plot twist and Beautiful writing), and a private note is visible only to you.

To skip typing, use Scan Text from the iPhone keyboard on a printed page. That is an iOS feature, so Bookstub does not use the camera for it. Each line can become a share card with the title, the author and the page as attribution. The lines and tabs page lists every option.

How much quoting is too much?

Keep quotes short. A line or two is a note. A full page typed out is a copy, and you are responsible for what you save and share. If you want to share a quote, include the book, the author and the page, so that anyone can trace it back.

How do you use your annotations later?

Set a review rhythm. Once a month, flip through the books you finished and read your marks. Once a year, collect the best lines into one list. That year-end list is often the most valued part of a reading life, and it exists only if you marked the pages when you read them. The routine in the guide to remembering what you read shows how to fit it in.

What are the downsides of heavy annotation?

Too many marks defeat the purpose. A page with four colors of underline tells you that everything mattered, which is the same as nothing mattering. Heavy annotating also interrupts the pace of a story, and in a novel you often do better with a light touch: flag a handful of lines and let the plot carry you.

Set a soft limit, such as five marks per chapter in nonfiction and three per chapter in fiction. The limit forces you to choose, and the choosing is where the memory work happens.

What does a well-marked page look like?

Imagine a page of a history book. A vertical line sits beside a paragraph that explains a cause. A star marks the sentence you will use in an argument. A question mark sits beside a date that looks wrong, with a note to check. In the top corner, a two-word note says compare to ch. 2.

That is four marks on a page, each with a clear meaning. When you return in a year, your eye lands on them in seconds, and the rest of the page can stay quiet.

Which tools are worth owning?

Very few. A soft pencil, a fine pen, and one pack of thin removable flags are enough. Highlighters bleed through thin paper and fade, so pencil marks and flags age better. Keep the tools with the book so that you annotate when the thought occurs.

For digital reading, the default highlight colors are fine. The real tool is a consistent code that you apply in every format, so that your marks mean the same thing on paper and on a screen.