Reasons to believe not only in this book but in music education at an early age (paraphrased from pbs.org):-Research has found that learning music facilitates learning other subjects and enhances skills that children inevitably use in other areas. -Making music involves more than the voice or fingers playing an instrument; a child learning about music has to tap into multiple skill sets, often simultaneously. For instance, people use their ears and eyes, as well as large and small muscles, says Kenneth Guilmartin, cofounder of Music Together, an early childhood music development program for infants through kindergarteners that involves parents or caregivers in the classes.-Benefits Language Development: According to the Children's Music Workshop, the effect of music education on language development can be seen in the brain. This relationship between music and language development is also socially advantageous to young children. -Increased IQ and The Brain Works Harder: The students in the study who received music instruction had improved sound discrimination and fine motor tasks, and brain imaging showed changes to the networks in the brain associated with those abilities, according to the Dana Foundation, a private philanthropic organization that supports brain research.-Improves Spatial-Temporal Skills: Research has also found a causal link between music and spatial intelligence, which means that understanding music can help children visualize various elements that should go together, like they would do when solving a math problem.

https://www.pbs.org/parents/thrive/the-benefits-of-music-education.