Srila Bhaktisiddhanta Saraswati Thakura (1874–1936) was born on the 6th February 1874 in Puri – a town in the Indian state of Orissa, famous for its ancient temple of Lord Jagannath. He was the son of Srila Bhaktivinoda Thakura, during his childhood he was always very interested in the Vedas and therefore memorised the Bhagavad-Gita, and found realisation in his father's philosophical works.
Not only he learnt from his father's writings, he also published many authorised shastras: Bhagavad-Gita, Srimad Bhagavatam, Caitanya Bhagavata, Caitanya Mangala, Prema-bhakti-candrika, and his favorite book Sri Caitanya-Caritamrta. He predicted that foreigners would learn Bengali and learn from the nectar left by Srila Krishna Dasa Kaviraja in the Caitanya-Caritamrta.
For us to understand the importance of Srila Bhaktisiddhanta Saraswati Thakura we should try and understand at the history of the Gaudiya Vaishnavism as well as the International Society for Krishna Consciousness (ISKCON).
Srila Bhaktisiddhantha said that Srila Visvanatha Chakravarti Thakura was the guardian of the Gaudiya Vaisnava tradition during the XVII century.
During the XVIII century it was a difficult time as India was going through various hardships due to European invasions, British penetration etc. During this period there was a proliferation of pakrita sahajias causing lots of confusion in our tradition, so Srila Bhaktivinoda Thakura and Srila Bhaktisiddhantha Saraswati Thakura had a very important influence in re-educating the devotees with the real perspective of Sri Caitanya Mahaprabhu's movement.
He asked his disciple A. C. Bhaktivedanta Swami Prabhupada to go to the Western world and teach Krishna consciousness. Srila Prabhupada went to New York in 1965 and carried on his spiritual master's mission with full commitment, for the pleasure of his spiritual master, Srila Prabhupada founded ISKCON.
"Let me not desire anything but the highest good for my worst enemy."
If you would like to know more about this important saint in our tradition, here is a lecture from Param Gati Prabhu (in Portuguese) on the appearance of Srila Bhaktisiddhantha Saraswati Thakura.