Hearing is a prerequisite for the evolution of language and thus the development of human societies. It is the only major sense whose evolution can be traced back to vertebrates, starting with sarcopterygians.

The book explores the evolution of auditory development that has remained largely unexplored in contemporary theories of neurosensory brain evolution, including the telencephalon. It describes how sensory epithelia from the basilar papilla evolved in the ear and connected dedicated cochlear neurons to neuronal centers in the brain, and deals with how sound is converted through sound modulations into reliably decoded messages.

The loss of hearing with age is expected to reach 2.6 billion people by 2050. As such, the book explains and reviews hearing loss at the molecular level to the behavioral level, and provides suggestions to manage the loss.