
Life of the master
Swami Vivekananda was born as Narendranath Dutta,in Calcutta, to a bengali kayastha family, in 1863.
Narendranath was interested in spirituality from a young age and used to meditate before the images of deities such as Shiva, Rama, Sita, and Mahavir Hanuman. He was fascinated by wandering ascetics and monks and at the same time he was naughty and restless as a child.
Narendra became part of multiple social religious movements during his youth. In 1880 he joined Nava Vidhan,a religious movement to reinterpret hinduism principles in modern light,founded by keshub chandra sen.
He was an avid reader and studied a wide range of subjects including philosophy, religion, history, social science, art and literature. He was trained in Indian classical music, regularly played sports and organised activities. He studied Western logic, Western philosophy and European history from the General Assembly’s Institution. While studying western philosophers he also studied bengali and sanskrit literature. Thus he had a good knowledge of both East and West.
He completed his BA degree in 1884. During his school and college days he was good in both academics and sports.
He then became a part of the freemasonry lodge sometime before 1884, then sadharan brahmo samaj, a breakaway of brahmo samaj.He was aslo active in Band of Hope, a social movement to discourage youths from doing alcohol.
Exposure to many religious organizations with their own reforming principles made him ask the fundamental question : “How to experience God?”
He asked many prominent calcutta residents “Have u seen god?” but none could give a satisfactory answer. One day,in 1881, he met Ramakrishna paramahamsa and asked the same question, to which ramakrishna replied “Yes, I see Him as I see you, only in an infinitely intenser sense.”
Narendra was satisfied with that answer and decided to learn from him.
in 1884 Narendra’s father died and his family was bankrupt. In such bad family conditions, Narendra found solace in his visits to Ramakrishna.He rapidly learnt from him
in 1885 Ramakrishna was diagnosed of throat cancer and he was moved to a rented villa in Cossipore where his disciples including Vivekananda took care of him. Inspite of poverty and joblessness he joined the group of disciples as a leader.
He was known for his miraculous memory powers and speed reading. Once he requested some books written by Sir John Lubbock and returned it the next day claiming that he had read them. The librarian found out he was speaking the truth, upon cross examination.
At cossipore Narendra experienced nirvikalpa samadhi.
There in cossipore, Ramakrishna handed over ochre robes to his disciples and thus began their monastic order.
After Ramakrishna died in 1886, Vivekananda and other fellow disciples moved to a dilapidated building in Baranagar. They formed the new monastic brotherhood, Ramakrishna Math , and in 1887 took the formal vows of Sannyasa.
Narendra thus became Swami Vivekananda.
After Ramakrishna’s death his followers stopped supporting Vivekananda and his fellow monks. They begged on the streets for survival.
In the Baranagar math , the group practiced austerities and meditated. Vivekananda heard the call for the greater mission of his life. He decided to explore India. In 1890, taking blessings from Sarada Devi, he left as a parivrajaka, a wandering monk. He lived on Bhiksha(alms), travelled by foot and rail. He stayed with people of different strata of society- scholars, kings, dewans, christians, muslims, low caste workers on the way.
Throughout the journey he realised the appaling poverty and backwardness of the masses. He realised that the masses needed two kinds of knowledge: secular knowledge to improve their economic condition, and spiritual knowledge to infuse in them faith in themselves during hardship. An organization was necessary.
He got to know that the World Parliament of Religions was being held in Chicago in 1893, and decided to go there, to introduce hinduism to the west and also to get support for establishing the organization he desired.
At the end of his travels in India, he reached Kanyakumari on December 24, 1892, where he meditated on a rock 500 m far from Kanyakumari mainland. Vivekananda Rock Memorial was built on the same place in 1970 in his honour.

He left for America in May 1893, travelled to China, Japan , Canada before reaching US and reached Chicago in July 1893.
In September 1893, he gave his speech at the world parliament of religions in Chicago, which made him very famous in the west.
His words “Brothers and sisters of America” got him a two minute standing ovation from 7000 strong crowd.
After the parliament, he spent nearly 3 and half years in the US and UK, giving lectures and classes on vedanta and yoga.
His taught yoga by the 4 yogas model: Jnana, Bhakti, Karma and Raja Yoga.

He established the Vedanta Society in New York in 1894.
In November 1895 he met Margaret Elizabeth Noble, an Irish woman, who would become known as Sister Nivedita.
In 1897 he returned to India,and he was welcomed enthusiastically everywhere he went. He gave series of lectures throughout india.
In 1 May 1897, he founded the organization he desired, Ramakrishna Mission, in which monks and lay people would jointly undertake propagation of Practical Vedanta, and various forms of social service – running hospitals, schools, colleges, hostels, rural development centres , conducting massive relief and rehabilitation work for victims of natural disasters in parts of India and abroad.
In 1898 he acquired a plot of land in Belur and established the Belur math, or Ramakrishna Math, a official place of the monastic order started in Baranagar started in 1886.
In 1899 he again went to US, delivering many lectures. He returned back to Belur Math in 1900, and in 1902, breathed his last.
He left his body while meditating in 1902, and according to his disciples he attained Mahasamadhi.
He was one of the stalwarts in pre independence India to uplift the masses socially and spiritually in a large scale. Many freedom fighters were influenced by Swamiji- SC Bose, Gandhi, Lokmanya Tilak, Rabindranath Tagore.
Organization
Ramakrishna mission

Ramakrishna Mission was founded by Swami Vivekananda in 1897, in honour of his guru Ramakrishna Paramahamsa. The organization chiefly propagates the Hindu philosophy of Advaita Vedanta and four yogic idealsājnana, bhakti, karma, and Raja Yoga. Apart from religious and spiritual teaching the organization carries out extensive educational and philanthropic work in India.This aspect came to be a feature of many other Hindu movements. In the history of indian spirituality, it was the first such institution which catered to the society as well as to the monks. It has 201 centers around the world and publishes many important Hindu texts. It is affiliated with the monastic organisation Ramakrishna Math, with whom it shares members. Today it has over 205 centres worldwide with philanthropic and educational activities. The Math runs:
Vedanta Society
Branches of Ramakrishna Mission outside india are generally known as Vedanta Societies.

The first Vedanta society was established by Swami Vivekananda in New york in november 1894- Vedanta Society of New York
Now there are 55+ Vedanta societies in 20 countries all over the world, with more than 30 in the US alone.
Advaita Ashram
Located in Mayavati, in Champawat district in Uttarakhand is an ashram dedicated to the study and dissemination of advaita vedanta.
It was established in march 1899 by two british disciples- Captain James Henry Sevier(ex British Indian Army officer)and Charlotte Elizabeth Sevier, his wife , with the help of Swami Swarupananda.
There are no shrines in the ashram and its primary purpose is the study, preaching and practice of Advaita- philosophy of non dualism.Vivekananda himself visited the ashram in 1901.
Today it publishes Prabuddha Bharata , an english monthly magazine , which was started by Vivekananda himself, besides the other works of Vivekananda.Besides the publishing activities , it runs charitable hospital and other welfare activities nearby.

It also runs a website http://www.advaitaashrama.org/ where many teachings of vivekananda are made available to the public free of cost, online.
Teachings
All the speeches given by Vivekananda throughout the world has been compiled by the devotees, named as “The Complete works of Swami Vivekananda”, and is available in the website https://advaitaashrama.org/cw/content.php, as well as in the app, “Full Works Vivekananda”, completely free.

His work is a very good introduction to spirituality. He touched every aspect of Hinduism, and talked about major religions of the world and their historical and mystical aspects. If you are a person having no knowledge of spirituality, his work is a great introduction to that.
References
Vedanta Centers and Societies