There is a trend of summaries that promise to deliver the core ideas of a book in minutes. I understand the appeal, and I do believe summaries have value; however, I don’t believe that a summary replaces the book or any long-form media. Summaries are a different medium and serve a different purpose.
A summary provides you the conclusions without context. Sometimes this is enough. For example, if an FDA trial finds a new drug to be safe and effective, I believe most people would be willing to accept this and move on. But in other cases, the summary alone isn’t sufficient. Consider Michael Pollan’s seven-word summary of his book, In Defense of Food: “Eat food. Not too much. Mostly plants.” This summary also shares the key ideas of the text in short form, but it doesn’t stand alone in the same way. The FDA trial result provides a new piece of information that is validated by an institution. Michael Pollan’s book shares a perspective and belief system around food, which has little power without the supporting details in the book.
Fiction takes this one step further. A summary of A Farewell to Arms can give you the plot and even the themes, but it can’t replace the experience of reading hundreds of pages of Hemingway’s prose. Some of Hemingway’s magic is difficult to summarize: his short and direct sentences, stoic narration (even in the face of extreme events), and terse dialogue. A summary can of course cover these things and even provide examples, but it can’t deliver the feeling that Hemingway builds throughout the book.
This is not to say that books can’t be reduced in length. Many books could have a chapter removed without any impact (perhaps this would even improve the book). But shortening long-form media comes with a risk — the shortened version might inadvertently exclude the part that would have been the most impactful for you. Some of what impacts us we can anticipate. The rest are unknown unknowns, and no summarizer can predict those.
To summarize, when you read a book, you’re reading the author’s perspective on what’s important. They have already omitted items they deemed unnecessary. When you read a summary, you’re reading a different work — one written by the summarizer. I don’t think the answer is to stop reading summaries. They’re a useful tool, but a summary isn’t a replacement for the book; it’s something else entirely.