For all busy parents who don't have enough time to read books -other than your children's books ;)- I highly recommend listening to the audiobook "Free To Learn" by Peter Gray, an evolutionary psychologist and a reference in the Self-Directed Education movement. Peter Gray has a direct experience with the Sudbury model as his son attended Sudbury Valley School, the very first Sudbury school, during its early years.
He is also a research professor in the Department of Psychology at Boston College.
He writes a popular blog called "Freedom to Learn" for Psychology Today about the roles of play and curiosity as foundations for learning.
Amazon is offering a free Audible trial so you can enjoy the book for free while continuing your daily activities. (One of my former teacher colleagues who has also since then quit the traditional system told me that she was "'amen-ing' during the entire drive to work") ENJOY!