A thin book can leave more behind than a long one carries.

Length is a measure of pages, not of what stays. A short book that has been cut back to what it needs can rearrange something in a reader, while six hundred pages of comfortable elaboration can pass through leaving no residue at all. What lasts is compression rather than quantity, and compression is much harder to produce.

Reread a short thing you already own instead of starting a long one. When you write or speak, try cutting a third and see what survives. Most of what people remember from you will be a sentence, so it is worth finding out which one.