Writing Craft Guide

How to Write a Logline for Your Book

A logline is a one-to-two sentence description of your book that communicates protagonist, goal, obstacle, and stakes. It is the answer to “what is your book about?” that makes agents, publishers, and readers lean in. A good logline is not a summary — it's a promise.

1–2 sentences

Maximum logline length

Protagonist + goal + obstacle + stakes

The four elements every logline needs

Agents decide in 30 seconds

How long a logline gets to work

How to Write a Logline That Works

What a logline is and what it's not

A logline is not a summary. It does not trace the plot from chapter one to the end. It is a single compressed statement that captures what your book is essentially about: who wants what, what stands in their way, and why it matters. A logline does the same job as a film tagline or a back-cover hook: it makes someone lean forward. If your logline sounds like a book report rather than a pitch, it needs to be rebuilt from the premise up, not edited at the sentence level.

The four-element formula

Every effective logline has four components: protagonist (who), goal (wants what), obstacle (but faces what), and stakes (or else what). The formula is not a fill-in-the-blank exercise — it is a diagnostic tool. If your logline is missing any of these four elements, it will feel incomplete to an agent even if they cannot name why. Write the four elements separately first, then find the single sentence that fuses them. The fusion step is where the craft lives.

Protagonist — specific enough to be interesting, broad enough to be relatable

Your protagonist needs one or two defining characteristics, not a full biography. The most common logline mistake is either too vague (“a young woman”) or too specific (“a 32-year-old forensic accountant with a fear of bridges”). Aim for the level of specificity that creates immediate genre signal and emotional stakes. “A disgraced detective” is better than “a detective” and better than “a detective fired after a corruption scandal who now runs a failing PI firm.” One defining detail is the target.

Obstacle vs. antagonist — the structural difference

An antagonist is a character. An obstacle is a force — it may be a character, a system, a relationship, a secret, or the protagonist's own psychology. Loglines that name the antagonist (“a ruthless crime lord”) work well for thrillers and action stories where the conflict is external and personal. For literary fiction, domestic drama, or internal journey stories, the obstacle is often better framed as a situation or condition than as a villain. Match the framing to the actual shape of conflict in your book.

Stakes — why the reader should care what happens

Stakes are what is lost if the protagonist fails. They operate on two levels: external (the world, the mission, the survival) and internal (the identity, the relationship, the soul). The most compelling loglines have stakes at both levels. A thriller logline with only external stakes (“or thousands will die”) can feel generic. A literary logline with only internal stakes (“or she will never find herself”) can feel thin. Combine them: “or she will lose both her daughter and the only version of herself she has left.”

Common logline failures and how to fix them

The five most common logline failures: (1) Too long — if it takes three sentences, you haven't found the core yet. (2) Too vague — generic descriptors like “a woman discovers a dark secret” apply to thousands of books. (3) No stakes — the goal is stated but the consequence of failure is missing. (4) No obstacle — the protagonist wants something but nothing stands in their way. (5) Plot summary instead of premise — listing events rather than distilling tension. Each failure has one fix: go back to the four-element framework and rebuild.

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Frequently Asked Questions

What is the difference between a logline and a synopsis?

A logline is one to two sentences that communicate protagonist, goal, obstacle, and stakes. It is designed to intrigue and hook. A synopsis is a longer document — typically one to five pages — that summarizes the full plot including the ending. You use a logline to make someone want to read more; you use a synopsis to demonstrate that your plot is structurally sound. Both are required in most query packages, but they serve opposite functions.

How does a logline differ for literary fiction versus genre fiction?

Genre fiction loglines lean on external stakes: the villain, the clock, the physical danger. Literary fiction loglines often foreground internal stakes: identity, moral reckoning, a world that will never be the same. The four-element structure still applies, but “obstacle” may be internal and “stakes” may be emotional rather than physical. A literary logline should still be specific and create tension — vague character studies with no forward momentum don't work in any category.

Should a logline reveal the ending?

No. A logline is a hook, not a spoiler. It should establish the setup and the central tension — enough to make someone desperate to know what happens — without resolving that tension. The ending belongs in your synopsis, not your logline. Think of the logline as the back-cover copy version of your core premise: everything that makes someone pick up the book, nothing that makes them put it down satisfied.

How do you write a logline for a series?

Write one logline for the series arc and one for book one. The series logline captures the overarching premise and what changes across all books. The book-one logline treats that book as a standalone story: complete protagonist, complete obstacle, complete stakes, even if the larger story continues. When querying, lead with the book-one logline and mention the series context separately. Agents evaluate the first book on its own merits before considering the series potential.

Should your logline match your query letter?

Your query letter hook should be consistent with your logline, but the two documents have different jobs. The logline is a standalone tool — one or two sentences that work in any context. The query letter is a fuller pitch with word count, genre, comparable titles, and a longer summary paragraph. Many authors embed their logline directly into their query as the opening hook, which is an effective strategy: it gives the agent the core premise immediately before expanding into the fuller pitch.