In 1977, American esotericist Christopher Hills published the book "Nuclear Evolution: The Rainbow Body", which presented a modified version of Leadbeater's occult anatomy. Whereas Leadbeater had drawn each chakras with intricately detailed shapes and multiple colors, Hills presented them as a sequence of centers, each one being associated with a color of the rainbow. Most of the subsequent New Age writers will base their representations of the aura on Hill's interpretation of Leadbeater's ideas. Chakras became a part of mainstream esoteric speculations in the 1980s and 1990s. Many New Age techniques that aim to clear blockages of the chakras were developed during those years, such as crystal healing and aura-soma. Chakras were, by the late 1990s, less connected with their theosophical and Hinduist root, and more infused with New Age ideas. A variety of New Age books proposed different links between each chakras and colors, personality traits, illnesses, Christian sacraments, etc. Various type of holistic healing within the New Age movement claim to use aura reading techniques, such as bioenergetic analysis, spiritual energy and energy medicine.