Good question Sally. It depends on what the smell is. If you are refering to the musty smell older books often get, there are a number of treatments.
To start with get and air tight container. I use an old freezer in my garage.

1. Put the book in with baking soda, I use the new Flo-Thru boxes that Arm and Hammer came out with. This way if it falls over it will not spill out onto the books.

2. Put the book in with Charcoal. I put the charcoal in lids (this way when I take the charcoal from the freezer, I do not get it all over) that I have laying around and set them in with the book. How much charcoal is needed depends on how bad the book is.

3. If the smell is not too bad you may want to try putting in crumpled newspaper and leaving it.

4. If you have a rack that you can put into the container to keep it off the bottom of the container, you may want to try Kitty Litter. Put a layer of it on the bottom of the container than place the rack over the litter to keep the book at least 2" above it. Keep the container in a spot where it does not have to be moved until the book is ready to be removed. If the container is moved it may cause the dust from the litter to settle on the book.

The length of time the book is left depends on the smell. About once a week peek in and determine if the smell is gone, if not refresh what ever medium you used.
In some cases, some smell may remain, but the treatments will make them a less offensive.
Thank you Sally for the question, I hope this helps you.