The Vajrayana path seeks to eliminate all dualities, so that the practioner may realize the unity of enlightenment. This is done through use of rituals, symbolism and yoga practices to evoke experiences that enable realization.
Buddhist tantra is the foundation of Vajrayana and its systems of meditation. The guru-disciple relationship also is especially important in Vajrayana.
Vajrayana is practiced mostly in Tibet, Nepal, Bhutan and Mongolia. Some consider the Japanese Buddhist school of Shingon to be Vajrayana also.