How to Choose a Book's Title and Subtitle With SEO in Mind
Short answer: let the title be memorable and evocative (that's what makes a reader decide to buy), and use the subtitle for the specific keyword people actually search for. Both don't need to do the same job.
Why split these two jobs
A 100% descriptive title usually sounds boring; a 100% creative title adds nothing to search. The subtitle is the ideal spot for the long-tail keyword you identified, without sacrificing the main title's emotional hook.
Example structure
Short, evocative title + descriptive subtitle with the keyword: "[Memorable title]: [phrase that exactly describes the book's problem or promise, with the keyword included naturally]".
How to test it before publishing
Read it out loud: if it sounds forced, rewrite the subtitle, not the title.
Check that the subtitle's keyword is one you actually identified in your research (not one that sounds good but nobody searches for).
Compare against titles of similar, already-ranking books to calibrate the tone expected in your category.
A book's title and subtitle on KDP are among the most heavily weighted fields for Amazon's search algorithm, alongside the description and categories.
Official Amazon KDP documentation, 2026