The great scholar and encyclopedic writer Bu-ston is primarily associated with putting in order the accumulation of five centuries of vast quantities of texts that had been translated. The Buddhist centers at that time in India were largely destroyed. The Tibetans knew extremely well what they had learned and were able to put this knowledge to practical use regarding yoga and magic.
There were some disputes between some Orders regarding doctrine, not from doubts or questions, but due to various Indian traditions. Also, it seemed that their thoughts and imagination were paralysed by their faith in the word of the guru. But regarding these people who adopted Buddhism they were unequaled in such matters.
So the complicated task of elaboration, exposition and in analysing, cataloguing was done with consummate skill. Although much preliminary work had already been done on systematizing the texts that were finally included in the bKa'-'gyur (Kanjur, literally 'Translation of the Buddha-Word"), Bu-ston seems to have been almost entirely responsible for arranging the second and larger section, entitled the bsTan-'gyur (Tenjur, literally 'Translation of the Treatises") which included all the available translations of commentaries, exegetical literature and discourses by Indian Buddhist scholars and yogins. Many lamas were interested in helping with funds and academic labour, and when the work was finished the lamas of Rin-spungs and the Karma-pa order had very fine manuscript copies prepared.
The master manuscript copies were kept at Nar-thang, where very much later, in the eighteenth century, a printed edition was made in the traditional manner from carved wooden blocks. Bu-ston's work was really prodigious. He wrote on 'Perfection of Wisdom' literature and tantric texts generally with special reference to the Kalachakra (Wheel of Time) cycle of texts, and he also wrote a history of Buddhism in India and Tibet. Moreover, he ensured that the Tibetan versions of all texts included in the new compiled canon were carefully checked. Where necessary, new translations were made. This great compilation really marks the end of the labours of whole generations of Tibetan translations.
(Ref. D. Snellgrave & H. Richardson -- A cultural history of Tibet -- p. 169-170).
Tsong Khapa had a dream of Bu-ston. In this dream Bu-ston told him to go to Lama Chungpo Laye-pa who was of the Shangpa Kagyu lineage. When Tsong Khapa met this Lama, he told Tsong Khapa that he also had a dream and that Bu-ston told him that he would be coming. Lama Chungpo Laye-pa gave every teaching that he knew to Tsong Khapa and in this way Shangpa teachings dissolved into the Gelug-pa Lineage. Many of his works, pujas, tantras, etc.. are used by the Gelug-pa in their practice.
Bu-ston would have gained Buddhahood in his lifetime, but Pehar gave him a medicine (bay-cho) and a pen so his time was used doing Kalachakra commentary and astrology. He also spent much time being a doctor helping sick people.
At one time, Bu-ston's hand was ill so he asked Geshe To-may-zampo, (who wrote "Seventy verses of Bodhisattva" and who had meditated on Bodhicitta and gained Buddhahood), to blow on his hand to cure it. Bu-ston repaired lived at the Shalu monastery. At this monastery, Bu-ston had a great following and he gave vows to 10,000 monks. He was 75 years old when he died on June 21 and went to Tusita.