It’s all right if you see other publishers. In fact, I encourage it.
That comment is in response to a question recently asked by an author we have under contract. The question was whether it was considered proper etiquette to submit his new book to us for consideration before submitting it to other publishers and agents. My advice is very simple:
Do what’s best for your book.
There are many reasons authors consider different publishers for their manuscripts. One common reason is that an author may publish with a small press, like Divertir Publishing, and then find an agent for a subsequent work. The agent will also want to do what’s best for the new book, which might be to shop it to larger publishers. Another reason is that the publisher for one of your books may not handle the genre for you new manuscript. We don’t publish erotica or books with what we consider to be excessive sex or violence, and we don’t publish memoirs unless they contain a social message. Does that mean books that contain sex and violence or memoirs without a social message won’t be fantastic books? Certainly not. What it does mean is we aren’t the right publisher for these works because of our tastes.
Many famous authors published with multiple publishers, including Dr. Seuss (his first book, And to Think That I Saw It on Mulberry Street, was published by Vanguard Press, while The Cat in the Hat was a joint venture between Houghton Mifflin and Random House). Suzanne Van Rooyen (whose first novel Divertir published) had her next two books published by two different publishers. To be honest this does not hurt us in any way and might help – the fact there are more publishers displaying her works makes it more likely that readers will discover her writing (which could only help sales of her first book). If Suzanne were to land a deal with Random House tomorrow I would be a very happy person, because we were the ones to discover her (we were looking for short stories for one of our collections and came across one of her stories, which it turns out she had turned into a novel). Call it bragging rights.
I would say there is one exception to the above. If you send a publisher or agent a manuscript, the agent or publisher may take the time to send a detailed critique with suggested improvements. If you use some of the suggested changes from the critique to revise your manuscript, then I do think as a courtesy you should send the revised manuscript to the agent or publisher again for review. After all, they have taken the time to provide feedback, which demonstrates a level of interest. Including in your query letter that you took their comments to heart in your revisions is probably the best way to get the book reviewed a second time. If the agent or publisher does not review the manuscript or offer a contract, then I would ask the person who provided the critique if you can use the ideas from the critique in your work as you query other agents and publishers (asking as part of your query letter is probably the simplest way and shows you are a professional who takes the intellectual property of others seriously).