Remember, they receive many queries, just like yours, so you will need to compete for their attention. Depending on the preference of the individual publisher, you can send them the query and synopsis or you may be invited to include three sample chapters. This gives them a good idea of your writing style and theme. As mentioned earlier, the alternative to print publishing is epublishing. This is also the latest incarnation of self-publishing.
Some people look down at self-publishing.
I don't know why. Some of the greats of our profession have published their own work. And let's not forget bestselling titles like The Joy of Cooking, The Celestine Prophecy and The One Minute Manager all started life as self-published books. When it comes to epublishing, here again, you have two choices. You can produce your own ebook and then distribute it through one of the many epublishers online.