In the prayer to St Sergius of Radonezh it is said : "You came closer to God than any other earthly man". Saint Sergius revived the monastic ascetic practices in Russia and founded many monasteries. He trained a multitude of monks-ascetics who in their turn founded hundreds of monasteries which enlightened the east and the north of Russia. Saint Sergius was also a wise counsellor and inspirer of Russian Princes and he helped establish the Russian state under the rule of the Great Prince of Moscow Dimitri Donskoy. With the blessing of Saint Sergius, Dimitri Donskoy stood up bravely against the Tatar Khan Mamay and defeated him in the bloody Kulikovskaya battle. Thus the Great Prince made the first important step in shaking off the Tatar yoke. There were no books written about Saint Sergius during his life, because of his remarkable humility. The first book about him was written by his disciple Epiphanios the Wise 26 years after Saint's death. Nowadays there are more than a dozen books about Saint Sergius but that by Metropolitan Philaret of Moscow is considered to be the best. This book however is meant for ceremonial reading during church services and therefore many precious details of the life of the Saint are left out. This present work is a re-telling of mainly two books: "The Life of Saint Sergius" by hieromonk Nikon (Rozhdestvenski) and "Saint Sergius of Radonezh and the Trinity Monastery, established by him" by the academician E Golubinski. The reader will learn the main events in the life of Saint Sergius, his spiritual visions and the testimonies of his disciples. The original texts were shortened and set in modern language, in order to make them better accessible to the reader.