His message of divine unity (Tawhid) focused on the themes of love, harmony, and beauty. He taught that blind adherence to any book rendered religion devoid of spirit. Branches of Inayat Khan's movement can be found in the Netherlands, France, England, Germany, the United States, Canada, Russia and Australia. In his various written works, such as the Music of Life and The Mysticism of Sound and Music, Inayat Khan interlocks his passion for music with his Sufi ideologies making an argument for music as the harmonious thread of the Universe.