• Writing a book summary helps you remember what you read months, or even years, after reading.
• It helps you connect main concepts from other books, giving you a deeper level of understanding.
• Lastly, it helps you improve your own writing.

Writing a book summary consists of three steps.

1. Take notes while you read.
2. Write the main takeaways in your own words.
3. Continue to summarise over time (progressive summarization.)

• If you read a printed book, highlight important quotes, ideas, or questions. Write the page number on the first blank page.
• If you're reading a Kindle book, use Kindle's "notes" and "highlights" to collect important takeaways.
• Highlight the book's chapter headings as you're reading. For books, where each chapter builds on the last, it will be easier to get an overview of your notes and highlights.

• If you're reading a print or hardcover book, write your notes and highlights into a word processor or note-taking app.
• If you're reading a Kindle book, add your notes, then export your notes and highlights. Copy them into a preferred word processor or note-taking app. Remove all the irrelevant markings, like "Read more at location {NUMBER]", "Add a note".
• Now, rewrite each highlight in your own words.
• If you highlighted chapter headings, change them into subheadings.

Use progressive summarization to distil the ideas: Summarise your notes, then summarise that summary, then summarise that summary.

There are five layers to progressive summarization.

1. The book's notes and highlights are unedited and lack context.
2. Solve the context problem by summarising the book in your own words.
3. Highlight the key takeaways that are not context-specific.
4. Bold small instructions that tell you what to do.
5. Remix and combine ideas to create content. It is best done over time.