Ramakrishna (February 18, 1836 – August 16, 1886), was a famous Bengali sage and mystic of 19th-century India. Ramakrishna proclaimed the oneness of all religions and the worship of the blissful Divine Mother. Many of his disciples and devotees believe he was an avatar or incarnation of God. He is also referred as Paramahamsa by his devotees, meaning “Great Swan”.  He gave everyone the freedom and power to pursue Truth along his or her own unique path.
A Brief History
Ramakrishna was born in a poor Brahmin Vaishnava family in rural Bengal. According to traditional accounts, Ramakrishna’s parents experienced supernatural incidents, visions before his birth. His father Khudiram had a dream in Gaya in which Lord Gadadhara (a form of god Vishnu), said that he would be born as his son. Mother Chandramani Devi is said to have had a vision of light entering her womb from Shiva’s temple. 
Ramakrishna describes his first spiritual ecstasy at the age of six: while walking along the paddy fields, a flock of white cranes flying against a backdrop of dark thunder clouds caught his vision. He reportedly became so absorbed by this scene that he lost outward consciousness and experienced indescribable joy in that state. Ramakrishna reportedly had experiences of similar nature a few other times in his childhood—while worshipping the goddess Vishalakshi, and portraying god Shiva in a drama during Shivaratri festival. From his tenth or eleventh year on, the trances became common, and by the final years of his life, Ramakrishna’s samādhi periods occurred almost daily. 
He became a priest of the Dakshineswar Kali Temple, dedicated to the goddess Kali. He began to look upon the image of the goddess Kali as his mother and the mother of the universe. He became seized by desire and longing to have a darshana (vision) of Kali—a direct realization of her reality—and believed the stone image to be living and breathing entity.
Rumors spread to Kamarpukur that Ramakrishna had become unstable as a result of his spiritual exercises at Dakshineswar. Ramakrishna’s mother and his elder brother Rameswar decided to get Ramakrishna married, thinking that marriage would be a good steadying influence upon him—by forcing him to accept responsibility and to keep his attention on normal affairs rather than being obsessed with his spiritual practices and visions. Far from objecting to the marriage, Ramakrishna mentioned that they could find the five-year-old bride, then known as Saradamani Mukhopadhyaya, at the house of Ramchandra Mukherjee in Jayrambati. Later known as Sarada Devi, the marriage between the two is seen as one of the most spiritual and perfect unions between a man and a woman.  Lex Hixon has written “We know that she and Sri Ramakrishna were the same Reality, the same Soul, the same infinite Light manifesting through two bodies.” 
After his marriage, Ramakrishna returned to Calcutta and resumed the charges of the temple again, but instead of toning down, his spiritual fervor and devotion only increased. Many of his religious views were based on traditional Hindu thought and practice. He believed that every religion was welcome, and that worshiping a god in any way was better than not worshiping one at all. He became very known for his views on religious tolerance and was seen as a saintly figure to many because of them. 
From 1861 Ramakrishna absorbed at a tremendous rate the teachings and initiations of many traditions, including Tantra, Kundalini Yoga, and many Hindu philosophies, even absorbing the esoteric teachings of Islam and Christianity.
As his name spread, an ever-shifting crowd of all classes and castes visited Ramakrishna. In his ever-present state of heightened awareness the God-intoxicated Ramakrishna would hold audience with many seekers, friends, and dignitaries, sharing stories of spiritual life, singing songs, answering questions, and otherwise inspiring to dizzying heights the crowds who showed up. At the heart of it says Lex Hixon, “his manifestation was basically the inspiration of Divine Mother, the inspiration of God as feminine.” 
Ramakrishna practised several religions, including Islam and Christianity, and recognized that in spite of the differences, all religions are valid and true and they lead to the same ultimate goal—God.Ramakrishna’s proclamation that jatra jiv tatra Shiv (wherever there is a living being, there is Shiva) stemmed from his Advaitic perception of Reality. His teaching, “Jive daya noy, Shiv gyane jiv seba” (not kindness to living beings, but serving the living being as Shiva Himself) is considered as the inspiration for the philanthropic work carried out by his chief disciple Vivekananda. 
Excerpts from “Great Swan: Meetings with Ramakrishna”
About Great Swan: Great Swan: Meetings with Ramakrishna by Lex Hixon is a dramatic retelling, for contemporary Westerners, of a series of encounters with the great Bengali sage Ramakrishna, who proclaimed the oneness of all religions and the worship of the blissful Divine Mother. By turns playful, brilliant, tender, and visionary, Ramakrishna offers in this breathtaking book practical instruction, inspiration, and thrilling glimpses into his state of spiritual intoxication as he meets with devotees and visitors in his room beside the holy river Ganges:
From Chapter 2:
Ramakrishna: O beloved friends, please listen to my words! The sole purpose and goal for human life, the supreme ideal of which all other ideals are simply an expression, is to cultivate love—the most pure, passionate, intimate love that the milkmaids and cowherd boys in the green groves of Vrindavan cherished for the captivating, dark blue Krishna, the very incarnation of Divine Love. There is no boundary whatsoever to pure love—it embraces humanity and Divinity equally. In this most intense love, no sense of duality can remain. When Lord Krishna traveled to the city of Mathura to fulfill his administrative duty,’ his companions roamed the fragrant countryside, weeping with ecstatic love, their outward separation from Krishna’s beloved form further intensifying their inward union with him as Divine Presence, as Love.
From Chapter 3:
The radiant atmosphere of Ramakrishna’s room and its alchemical power move with him, creating the spaciousness and tranquillity of the Dakshineswar Temple Garden wherever the Paramahamsa travels to meet with lovers of God and other persons of integrity, consecrated to truth, wherever they may be. With all such persons, our Master feels intense affinity and solidarity.
Today we are delighted to be in his blissful company, riding in the cab of a horse-drawn carriage through the colorful streets of Calcutta— a city of cultural and intellectual ferment and creativity, where ancient and modern currents meet, colliding and blending. The Paramahamsa is seated cross-legged in the noisy, bouncing vehicle, immersed in the profound silence which arises as his mental and perceptual faculties become aligned and are drawn like iron filings to the powerful magnet of the Absolute.
Unexpectedly, the God-intoxicated sage enters another mood. He is now leaning dangerously far out of the carriage window, embracing with ecstasy every passing detail of the city, crying out drunkenly to the patrons of wine shops and perfume stalls: “Yes! You are experiencing a drop of divine Bliss. But go further!” This admonition and encouragement to go further continuously along whatever path presents itself is the essential teaching of Ramakrishna. “There are an infinite number of perspectives,” he passionately proclaims, “and each one of them is a path to God.” He often tells the story of the woodcutter who, journeying further and further lto a forest to find suitable trees, happens upon a precious grove of sandalwood. As the impoverished man stands in astonishment, contemplating his exceeding good fortune, a wandering sage appears and counsels him with the simple words: “Go further! Go further!” The woodcutter ponders this pithy instruction and ventures further into the wilderness, where he discovers a rich vein of gold. The initiatory words of the sage spring up spontaneously in his mind and he continues his quest, eventually discovering a cave filled with diamonds. Some practitioners are still ordinary brushwood, others sandalwood, still others gold, while the mature of the mature have become clear diamond. Ramakrishna’s only function is to accelerate this alchemical process. He often remarks: “I would sacrifice twenty thousand incarnations to encourage even a single seeker of Truth.”