The first place to look is in your copy of the Writer's Market. If you don't have one, most local libraries have one or more copies of this valuable writer's resource. Another place to look is online. Several sites contain writer's guidelines to book publishers. Once you have a compiled a list of publishers that publish what you write, you need to evaluate them.
Small publishers are different than the larger ones.
With the large publishers, if your book is accepted, you have more of chance of selling well in the marketplace because they have more money available to advertise your book. Larger publishers are also more likely to pay you more for your book in the form of an advance against future royalties. Smaller publishers also have their advantages. With the smaller ones, you have a better chance of having more attention from those working with the publisher. Smaller publishers have more of a family atmosphere while the larger ones with their many on-going projects have more of a get business done attitude.