Or maybe not.
Actually, probably not.
In truth, I would say definitely not.
Your manuscript may not be ready to be published, but it is probably ready to receive some feedback! And no, I don't mean that you should have your mom or your kids or your best friend read it (though that's certainly okay to do). I mean that you should seek objective feedback from industry professionals. Or, at the very least, other writers you trust to be completely, brutally, honestly constructive.
Once you've done that, you'll probably (definitely) need to revise. Some of this will be easy. Fixing typos and grammar, rewording lines to make them more clear--these kinds of things are simple and expected. But what if someone tells you your story doesn't work? What if the whole thing made them bored out of their minds or left them wondering what the heck was going on? Worse, what if you get CONFLICTING feedback? (the horror!)
Calm down. This is all part of growing as a writer. Chances are if someone's feedback resonates with you, it is correct. On the other hand, if it doesn't, it may mean that you aren't being objective. Or it could mean that the person giving you feedback doesn't know what the heck they're talking about. If this happens, sleep on it. Seek more feedback. Try to be objective. Give yourself and your story a little space for a few days or weeks. Then, tackle your revision and polish that manuscript.
Now you're ready to publish your book!
You'll want to repeat that feedback/revision process a few times. Or a few hundred. However long it takes. It may be that you end up with a completely different story by the time you're truly done. It might make you crazy. It might make you curse yourself for ever pursuing this
Only you know what that is. And only you will really know when you're ready for the next step!
What is the next step? Read about that in Part 2!