While instructing a client on how to submit her book to Amazon to begin sales, I asked her to write a summary of the book. I realized afterward that I should have asked for a summation.

From a popular online dictionary:

Summary: a comprehensive and usually brief abstract, recapitulation, or compendium of previously stated facts or statements.

Summation: a review or recapitulation of previously stated facts or statements, often with a final conclusion or conclusions drawn from them.

They sound alike, yes, but for two things.

First, a summary is comprehensive. Can you say TMI?

Second, a summation needs a conclusion.

If you plan to self-publish, when describing your book, be sure to include what the purchaser should get out of it.

But remember, a summation, not a summary.