Henry Phelps is one of those writers who is best known through the work rather than the biography, and reliable public information about him is thin. What can be said with confidence comes from the audiobook itself, which is where we prefer to start in any case.
His subject is perception: colour and light as physical phenomena, and vision as the imperfect, endlessly interesting apparatus we use to interpret them. It is territory shared by painters, physicists and neuroscientists, and the writing sits deliberately at the junction, filed here under arts and entertainment rather than pure science because the emphasis falls on seeing as an artistic problem.
The approach is that of a guide rather than a lecturer. Nothing in the book asks for prior training, and the running time is modest enough to suggest an author more interested in clarity than in exhaustiveness. If you have ever wondered why a colour looks different at dusk, this is the shelf he is writing for.