Sri Ramakrishna is regarded as the Avatar of the modern age by millions of people around the world.
Being of recent times, his teachings have been well recorded, as well of his disicples.
The Ramakrishna Math and the Ramakrishna Mission have 208 centres all over the world : 157 in India, 15 in Bangladesh, 14 in USA, 2 each in Russia and South Africa, and one each in Argentina, Australia, Brazil, Canada, Fiji, France, Germany, Ireland, Japan, Malaysia, Mauritius, Nepal, Netherlands, Singapore, South Africa, Sri Lanka, Switzerland, UK and Zambia. There 41 sub-centers (18 within India, 23 outside India) under different centres.
Born on 18 February 1836 in Kamarpukur, a village about 120 kilometres to the northwest of Kolkata, Sri Ramakrishna had only the rudiments of school education. At a young age, owing to poverty at home, he became the priest of the Kali temple at Dakshineswar, newly built by Rani Rasmani. He could not continue his priestly duties for long, as he absorbed himself in his spiritual disciplines.
Possessed as he was by intense longing for God from his childhood, Sri Ramakrishna plunged into intense spiritual practices. After attaining the realization of God as the Divine Mother of the Universe, Kali, he followed the spiritual paths of different sects of Hinduism and the spiritual paths of other religions like:He started as a Bhakti - Devotion to God as Kali, then Islam, Christianity, Jñāna (Samadhi) - the way of knowledge, and finally Karma yoga as he dedicated himself to pass on his realizations to Vivekananda, Sarada Devi and a select number of disciples. He realized the Ultimate Reality through all these paths - thus there was one God!.
His spotless holiness, utter simplicity, extraordinary spiritual wisdom and love of God drew people to him like a magnet, and a number of sincere seekers gathered around him as his disciples.
Authors note: Sri Ramakrishna achivements were very similar to Sri Ananda Mayi Ma. Both had no education. Both started as Bhakta's. And both traversed many spiritual paths at great speed. The main difference is that Ma did not even experience birth into a body! But all knew from his boyhood that Ramakrishna was no ordinary child...
Ramakrishna Mission - founded by Swami Vivekananda: http://www.rkmdelhi.org/
Sri Sarada Devi: http://www.rkmdelhi.org/about-us/our-inspiration/sri-sarada-devi/
His major disciples: http://www.rkmdelhi.org/about-us/our-inspiration/direct-disciples/
Sri Ramakrishna’s main teachings are:
God realization is the ultimate goal of human life as that alone can bring man supreme happiness and peace. God is one, and is known by different names in different religions and sects. God can be realized through various paths taught in world religions. All religions are true in so far as they lead to the realization of the Ultimate Truth. God dwells in all people and so everyone, without the distinction of caste, creed or race, should be treated with respect and served with love.
Resources: Gospel of Ramakrishna http://www.vedanta-nl.org/GOSPEL.pdf