Download of Book2Speech 3.0.1 for Mac was on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. This free Mac application is an intellectual property of Claudio Guida. We recommend checking the downloaded files with any free antivirus. The software lies within Productivity Tools, more precisely Office Tools.
From the developer:
Book2Speech lets you convert a text into an audio track on the Apple macOS. It is based on the concept of "fragment", which can be created from the original text using several methods, for example, through the selection of the desired part. Each fragment is treated by the application as a separated object and can be modified, not only in its content, but also in its voice type and rate.
You may want to check out more software for Mac, such as Blurb Tally, which might be related to Book2Speech.