Sooner or later you will be asked this question if you work in book publishing.

It is possible to get a book published without an agent, but if your friend has written a blockbuster trade book (or any kind of trade book) having an agent will be a good idea. Although it’s not 100% true, it can be said that trade book editors talk to agents rather than aspiring authors.  Academic editors will almost always deal directly with the author, an academic. It’s probably best to assume your friend’s book falls into the blockbuster trade category and not get into a discussion about how narrow you may actually suspect their topic is. Tell them how to find an agent, and leave it to the agent to apply the discouragement — if that’s what ultimately in required. Of course you might reflect that you are probably not the best person to judge just what topic will or will not make for a great trade book (unless, that is, you are actually employed as a trade editor).

You can tell your friend to go to a bookstore and take a look at books similar to the one they have written. Look at the Acknowledgements or the Preface — authors will often give acknowledgement to their agent, especially if that agent has provided help “above and beyond”. If someone your friend admires likes this agent, your friend will probably like the agent too. And the existence of the book in itself demonstrates that the agent is interested in that sort of book. When writing an enquiry to an agent the aspiring author should not send a copy of the manuscript. At the most they might enclose an outline of the book. The letter of enquiry must include a sentence or two pointing out why the book needs to be published — the “hook”. However, most agents will give some direction on their website as to just what they’d like to see in a submission.

The Association of Authors’ Representatives maintains a website which has a search function, and provides lots of information about the process in general. (Click on the yellow link to go there.) AgentQuery has a “Quick Agent Search” which allows you to narrow down the search by type of book, and will say whether an agent is currently looking for new clients or not. If your friend is the sort who doesn’t think they’ve done enough if they haven’t been to the library and dug though huge reference books, direct them to the Literary Market Place, which lists lots of agents.

The experience of being rejected by an agent can be every bit as traumatic as being rejected by a publisher.  Just remember that agents don’t have endless capacity, and that their rejection of your book (or your friend’s) doesn’t mean it’s no good: just move on to the next name on the list and try again.