Vajrayana, or Tibetan Buddhism
This would be my main area ot study.
Wikipedia says this about Vajrayana: "Vajrayāna Buddhism is often viewed as the third major 'vehicle' (Yana) of Buddhism, alongside the Theravada and Mahayana. The Vajrayana is an extension of Mahayana Buddhism consisting not of philosophical differences, but rather the adoption of additional techniques (upaya, or 'skilful means')."
Buddhanet says: "This is the kind of Buddhism predominant in the Himalayan nations of Tibet, Nepal, Bhutan, and also Mongolia. It is known as Vajrayana because of the ritual use of the vajra, a symbol of imperishable diamond, of thunder and lightning. At the center of Tibetan Buddhism is the religious figure called the lama, Tibetan for "guru"," source of another of its names, Lamaism. Several major lineages of lamas developed, beginning in the ninth century with the Nyingma-pa. Two centuries later, Sarma-pa divided into the Sakya-pa and the Kagyu-pa. Three hundred years later, one of Tibet's revered lamas, Tsong-kha-pa, founded the reforming Gelug-pa."
Wikipedia article can be found here: http://en.wikipedia.org/wiki/Vajrayana
Buddhanet's Article can be found here: http://www.buddhanet.net/e-learning/history/b3schvaj.htm
Origins
Nyingma
The first human Teacher in Tibet was Padmasambhava, who founded the Nyingma School. The actual Lineage is different - The first Vajrayana Buddhist was The Primodoral Buddha, Samantabhdra, in Tibetan, Kuntuzangpo. He passed these teachings to Sambhogakaya Lama, Vajrasattva, and Vajrasattva gave them to the Nirmanakaya Lama, Prahevajra, or Garab Dorje - Who was an emanation of Vajrasattva, the first "Human Teacher" outside of Tibet. Before Garab Dorje transformed into light and disappeared, he gave Manjushrimitra a scroll with texts on it, and upon seeing it, he had the realization of his master. After Manjushrimitra was Shri Singha. Shri Singha found texts Manjushrimitra had hidden in a rock near Bodhigaya. Before he died, he gave the teaching to Jnanasutra. After Jnanasutra. was Vimalamitra. after Vimalamitra was Padmasambhava. After Guru Rinpoche (another name of Padmasambhava) was his female consort, and Buddha, and emanation of the Dakini Vajrayogini, Yeshe Tsogyal. After that was kongkhyen (Omnscient) Longchenpa, who is famous in Nyingma as a great scholar, and in all the other schools. After him was Rigdzin Jigme Lingpa. And after that, Jigme Gyalwe Nyugu. After that, Patrul Rinpoche, after that, Nyoshul Lungtok, after that, Khenpo Ngaga. This is where my lineage seperates from the rest. Our Lineage Lama studied with Khenpo Ngaga, but was not his main disciple. Chagdud Tulku Rinpoche is my Lineage Lama, and the Lama I studyy under, at the invitation of Chagdud Rinpoche, is Khentrul Rinpoche.
Image of my Perfect Lama:
May the Buddhas and teachers bless me
That I may explain definitively as I have remembered them,
Wonderfully profound, yet clear and easy to understand -
The unerring words of my perfect teacher.
A link to my Lama's Wikipedia article can be found here: http://en.wikipedia.org/wiki/Khentrul_Lodro_Thaye_Rinpoche
His wesbite is: http://orgyanshadrubling.com/
Most of the history of Nyingma follows in that order - Other schools were set up after Padmasamnbhava's death. This is the main lineage of Longchen Nying'thik. Longchen Nyingth'ik is the main "transmission" of Nyingma, but other lineages of texts include Longsel Nyingpo, Duddul Dorje, and Kat'hok.
Major Tibetan Buddhist (Vajrayana) figures, with images
Padmasambhava
Links to info about him: http://en.wikipedia.org/wiki/Padmasambhava , http://www.aroter.org/eng/images/statues/padma_statue.htm , http://www.tibet.com/Buddhism/nyingma.html , and http://www.khandro.net/GuruR_appendix.htm .
Atisha
Info on Atisha: http://www.kadampa.org/english/tradition/atisha.php , http://en.wikipedia.org/wiki/Atisha , http://www.lamayeshe.com/otherteachers/atisha/forward.shtml , and http://www.berzinarchives.com/bioghaphies/life_atisha.html .
Longchenpa
Info on him here : http://en.wikipedia.org/wiki/Longchenpa , and http://www.rangjung.com/authors/longchenpa.htm .
Jigme Lingpa