Clearly the agent in question was clueless. Or you could say that he was actually very clueful: he gave loads of clues but no actual answers.
Let's do some unpicking and see what we can learn. EA says that the category of your book is "perhaps THE most important question for an editor and his/her sales team." It's an important and possibly somewhat shocking lesson. There was you thinking it was your writing or even the story that was the most important. Of course it is, to you and your readers, but you and your readers will never see your book at all if the bookseller doesn't know where to put it.
See, booksellers have a simple system, which you may not like. They have it for a good reason: customers are simple souls who do not wish to look far to find a book. Customers think they know what they like, and don't want to be told otherwise, so they really need to know where they might find it. Fast. You might wish that a bookshop could be a glorious muddle of treasures just waiting to be found serendipitously, with a squeal of glee. "Oh, how wonderful! A part-monograph-part-travel-guide-part-poetry-collection-part-local-history-of-the-inner-hebrides! I normally read sci-fi but this sounds quite delightful." But what real readers want is the exact book that they want (even if they don't know what it is) just THERE, under the label that says "book that you want".
So, first thing to do when you pitch your book is to know what it is. This applies both to covering letters (see on-going competition) and to query letters; it certainly applies when the editor pitches your as yet uncontracted book to the sales/marketing team in the Acquisition Meeting; it also applies when you answer the casual question about your WIP: what's it about? Because before you say it's about a boy and a girl who get lost in the woods, you have to say it's a fairy tale about a boy and girl who get lost in the woods.
If you are innovative enough to have written a book that defies categorisation, be afraid. I did. I wrote a book called Blame My Brain. Now, luckily for me, I never had to pitch it to anyone as I already had a publisher and an agent and all that happened before commissioning was a conversation that went almost literally like this:
Chris (editor): Would you like to write some non-fiction?That afternoon I drafted a one-page plan and wrote the intro, and about three days later she'd come up with an offer.
C: What would you like to write about?
Me: The teenage brain.
C: Good idea.
Yes, I know. You hate me. I don't blame you. But I did take a long, long, long time to get to the point of having an editor trust me that much.
BUT, when it came to the bookshops deciding how to shelve it, then the fun began. Clearly, there is no category in any bookshop called "teenage non-fiction". (There may occasionally be a tiny little bit of a tiny dark shelf very near the floor, and occasionally when there is, I'm on my own in it.) Luckily - understatement - for me, booksellers thought the idea was so strong that they went out of their way to find a place for it but I still can't confidently predict when I go into a bookshop whether I'll find it in teenage/YA fiction, kids' non-fiction, psychology, parenting, popular science, neuroscience, mental illness or Scottish. (I joke not). Yes, this has been a problem. The only reason it was such a commercial success is that we got fab review coverage everywhere and there was nothing else on the market ticking the same boxes (still isn't - yay!); so word of mouth and market position now means that it doesn't matter that no one knows where to shelve it and no one knows where to find it. Well, it matters a bit ...
Anyway, that sort of situation is rare.
So, consider your WIP carefully, lovingly and calculatingly. Which shelf will it go on in the shops? I'll mention this and talk more about it - if I remember - in my Edinburgh Book Festival talk on How To Make a Publisher Say Yes on Aug 19th. (I don't mean it's about how to make a publisher say yes on Aug 19th - I hope a publisher will say yes on many other days as well). And do remember that it will hardly ever go in two sections, much as perhaps it should.
If you write for young people, in which age section of a bookshop will readers find it? I'll talk about the difference between 10-12s and teenage in my talk on Aug 20th. Again, a book that 10-year-olds AND 13-year-olds will love, will not be found in both 9-12 and the teenage sections.
However, there's more to categorisation than what shelf it will go on. We (humankind) like to pigeon-hole things. It's often an unattractive and unhelpful habit. Pigeon-holes are places of safety and comfort, but they are restrictive because you can't easily see out of them. However, while readers continue to be human and want categories, we have to work with them. And, actually, it is helpful when it makes us analyse the elements of our book, to make sure it ticks the right boxes or follows the right rules for that particular category or genre.
So, as well as knowing what section in the shop our book will end up on, we need to know in more detail what sort of book it is, so that we can describe it better and give people (agent, then editor, then marketing, then bookseller, then reader) a clearer idea as to why they might like it. Now, many books don't sit neatly within one pigeon-hole. And that's fine. No one ever said you had to sit neatly in the pigeon-hole. You're allowed to sit on the edge with your legs hanging out - it's a tad dangerous if you've had a bit much to drink, but just be aware of the dangers of alcohol and other substances and you can dangle to your heart's content.
But, while you're allowing your sci-fi book to dabble in romance or your historical novel to veer into magical realism, consider your reader. Are there enough readers out there who will go with you on your strange journey? Is your book like something else (something else successful - and not SO alike that you end up being cited in an anti-plagiarism fracas)? Does it fit a pattern? Are there good reasons why it contains several genre elements? Have you really got the experience to handle more than one? Are you genre-hopping because you haven't got your act together or have you genuinely thought this through?
If your book is a mixture of too many (say, more than two) genres, you are likely to lose readers. You are also likely to show a potential agent or editor that you haven't a clue what you're doing. Now you may well have a clue: you may be about to set a completely new genre-busting target of astonishing, innovative brilliance**: but the first page of your submission is not the place to tell your potential agent/editor this. Allow him to discover your avant-garde brilliance through your writing, not by leaping at him shouting BOO. Remember: eccentric brilliance often looks like crass lunacy at first sight and first sight is often all you get, if you're not careful. Later, the two of you can work out how you're going to pitch your magic to Sales and Marketing, but it will not be by telling them that it's a mixture of eighteen genres and hard to categorise.
** Edited to add: Have just seen a fabulous post by the inimitable Lynn Price, describing the inexcusable ignorance of the author who thought he was writing "literary action/adventure" - go read.
When you write, first consider your reader.
When you pitch, first consider your bookseller.
When you get your contract, first consider yourself: in my case, buy shoes, chocolate and sparkly wine.
There's no chocolate in that picture, for obvious reasons.