Maitreya Bodhisattva will be reborn in this world from Tuṣita 5.67 billion years after the Buddha's passing, and will save those remaining after the Buddha through three teachings.
Maitreya Bodhisattva is particularly revered in Shingon Buddhism. It is said that after Kōbō Daishi entered nirvana, he was reborn in Tuṣita Heaven, where he met Maitreya. Together, they will be reborn in this world.
Furthermore, since it is promised that he will surely attain enlightenment and become a Buddha, he is considered to be one with Mahāvairocana.
A portion of the proceeds from this book will be donated to various charitable organizations.