Why agents ask for them
A comp does in two words what a paragraph of description can't: it places your book. "For readers of X" tells an agent who the audience is, what shelf the book lives on, and roughly what a reader expects when they open it.
Comps also travel. The agent who takes you on will use them to pitch your book to editors, and editors use them to pitch to retailers. A good comp line keeps working long after the covering letter that carried it.
Good comps also vouch for you. They show an agent that you know the genre you're writing in and the readers you're writing for.
What makes a good comp
Recent. Books from the last few years work better than classics, because they show the market as it is, not as it was.
The same shelf. A comp should share your book's category and audience. A crime novel comped to a literary memoir tells the agent you're not sure what you've written.
Successful, but not stratospheric. Comping yourself to the biggest sellers in publishing history reads as naive, and it makes a claim about sales rather than about readers. Solid recent books that did well are the sweet spot.
Matched on something real. A comp doesn't have to share your plot. It can match your tone, your structure, your setting, or your voice. A pairing can split the work: "X meets Y" uses one comp for the world and another for the mood. A television series or film can serve too, for tone or audience, so long as at least one comp stays a book.
How to find yours
Read recent books in your genre, especially debuts; they're the books agents signed lately, which makes them evidence of current taste. Notice what sits beside your book's natural spot in a bookshop, and what the retailers' "readers also enjoyed" shelves put together.
If nothing fits perfectly, that's normal. Comps describe neighbours, not twins. Two books that each share something real with yours will do the job better than a hunt for an exact match ever could.
How to use them
One or two comps, in the covering letter, alongside the title, genre and word count. "For readers of X" and "X meets Y" are the standard shapes, and either is enough. There's no need to explain the comparison; if it needs explaining, it isn't placing the book.
Common mistakes
- The giant comp. "The next Harry Potter" is a sales forecast, not a placement, and nobody can back it.
- The classics-only comp. Austen and Tolkien show your flavour, not your market. Pair a classic with something recent if you must use one.
- The pile-up. Five comps place a book less precisely than two. Choose.
- The quality claim. "Written like Hilary Mantel" compares craft, and that's a verdict for readers.
- The obscurity. A comp only works if the agent might know it. A book nobody's heard of tells them nothing.
Comps make some writers anxious, as if naming similar books admits the manuscript isn't original. It's the opposite. Every book has neighbours, and knowing yours is a sign you know your area well.