Short answer it depends on what state you're selling from. Where is your business located?
In general, states require online sellers to register for a sales tax license just like any other business. Once you have the license then you're required to collect sales tax on items shipped to your state and then remit that back to the state.
I also know that some states handle books differently. Make sure your state considers books a taxable item before you do anything.
Hope that helps.
Definitely follow Mark's advice and configure your store based on what is appropriate for your business; consulting an accountant as needed.
Technically speaking, yes - you are in complete control of how you tax on Shopify.
In the Settings > Taxes area of your admin, you can set custom site-wide rates for your store based on region.
If you have some items that are taxable and others that aren't in your store, you can additionally set taxes at the product level.