Maybe...maybe not. Publishers are very conservative these days, as books sales remain fairly flat. So they don’t often have multiple open contracts open on any one writer, not unless they are fairly established. This is because they have no idea how you'll perform in the market, so they prefer not to tie up a lot of their money on a total unknown. In most cases, as a first time author, you'll be offered anywhere between a 1 and 3 book contract. If you're offered a 1 book contract, the publisher is being conservative--and that could be for a variety of reasons that have nothing to do with you. Don't panic. But if you've sold that 1 book on a full manuscript, don't imagine you can send them 3 more manuscripts right away and have them bought on a new contract as well. And what they will be willing to do for you will depend largely on the genre you're writing, your relationship with your editor, HER rapport with the powers that be. And of course, your option clause.

Because publishers will often wait and see how the public receives you before buying another book/offering another contract, this can mean up to a 2 year wait before you sell another if you're option clause isn't well worded (which we'll talk about later). This is where a good agent can really come in handy, but the point here is, you may not get a rocket start in this business--but don't assume that's because your publisher no longer has faith in you/has only interest in that one book. Like all fiscally-minded businesses, they're probably taking a wait and see approach.