Just like a rosary without any missing links, the Kagyu lineage has been passed down through an unbroken chain of masters and disciples. From both a long-line of Indian masters and the short transmission of Tilopa seeing face-to-face enlightenment itself (represented by the Buddha Dorje Chang), the Kagyu tradition was successfully passed down to Tibetan masters. They likewise achieved enlightenment through the practices of the Kagyu tradition, and have continued to pass down this tradition up to the present-day.
Integrating the Hinayana, Mahayana and Vajrayana Buddhism paths, Kagyu practices can bring realization to the practitioner in a single lifetime. Mahamudra known as the Great Seal or Gesture, is the meditation which brings forth the fruition of enlightenment in Kagyu practice. The Six Yogas of Naropa and the completion of three-year meditation retreats, usually accompanied by intensive study in monastic colleges are core practices of the Kagyu lineage.
The supreme holiness of the Karma Kagyu Lineage, the most wide-spread and thriving Kagyu tradition today, is the 17th Gyalwa Karmapa. The Karma Kagyu Lineage has been headed for centuries by the Gyalwa Karmapas. The 1st Karmapa, Dusum Khyenpa, was one of the principle disciples of Gampopa. Up until the present-day, the Karmapa has remained as one of the most outstanding, wise and compassionate leaders of Tibetan Buddhism.
The Karmapas are considered to be living examples of enlightenment, embodiments of the Bodhisattva of Compassion, known as Avalokitesvara or Chenrezig, and take birth solely to benefit others.
Information above is provided generously by Simhanada, The Lion's Roar.