Most people summarize by reading the whole thing and then trying to remember what mattered. That is backwards. A good summary is built in passes, and each pass throws away more than it keeps.
01Skim the skeleton
Before reading anything closely, spend ninety seconds on structure alone. Read every heading, the first and last sentence of each section, any bolded terms, and the captions on tables and figures. You are not trying to understand the argument yet, only to build a map of where it lives. When you start reading for real, you already know which sections carry the weight and which are throat-clearing.
02Mark the load-bearing lines
Now read once, forward, and mark only the sentences a claim would collapse without: the topic sentence of each paragraph, every number, every named entity, and any sentence that begins with a word like therefore, however, or we found. Resist highlighting things that are merely interesting. A summary is defined by what it leaves out, and the discipline starts here.
03Compress each section to one line
At the end of each section, look away from the page and write a single sentence that captures it in your own words. Your own words is the important part: paraphrasing forces comprehension in a way that copying never does. If a section resists compression to one line, that is a signal you have not found its point, so go back before moving on.
04Stitch, then cut thirty percent
String your one-liners together in order. That draft is your summary, and it is too long. Cut roughly a third: merge lines that repeat, drop the ones that turned out to be supporting detail once the whole is visible, and lead with the single most consequential finding rather than the document's own opening. The cut is not trimming, it is the step where a pile of notes becomes something someone else can act on in thirty seconds.
| Pass | What you keep | Time (10-pg doc) |
|---|---|---|
| Skim the skeleton | Headings, first/last lines, figures | 1.5 min |
| Mark load-bearing lines | Claims, numbers, names | 6 min |
| Compress to one line | One sentence per section | 4 min |
| Stitch and cut 30% | The final summary | 3 min |
How long should a summary be?
Aim for five to ten percent of the original for a document, one to three sentences for an article. If it runs longer, you are excerpting, not summarizing.
Does this work for a 300-page book?
Yes, at the chapter level: run passes one and three on the table of contents and chapter openings, then only deep-read the two or three chapters that carry the argument.
What is the biggest mistake?
Highlighting too much. If half the page is marked, nothing is. The four-pass method works because each pass is allowed to discard more than the last.
Summarizing at volume, not one page at a time?
Summarize Pro batches PDFs, papers and reports, every key claim cited to its source page, exports to Word or Excel. The free tool is for one page; Pro is for the pile.