Legal Question in Intellectual Property in Texas

Assuming the book is subject to copyright protection, then yes, you would be infringing the owner's copyright.

Not so quick. Most authors would love to have someone do an audio reading of their book and even sell it, for a fee, which might be surprisingly low and which might be royalty based so that you only pay if you get paid. There is a win-win opportunity here, since you are proposing to add value to the copyrighted material. Call the publisher and ask. You might be pleasantly surprised at the response if you know how to pitch this to them. A good copyright lawyer could help you with the pitch or, better yet, do the pitch so all is legal. One further thought...if the book is more than about 70 -90 years old, then it may be public domain, although I am assuming from your question that is not the case here.