Gurdjieff is arguably one of the great minds of the 20th century and is considered by some people as a precursor of the "New Age" movement, a father of modern ecology and a person who inspired a new outlook on the development of man's consciousness.Who was Gurdjieff? It is difficult to define him precisely. Such common labels as 'philosopher', 'guru', 'messiah' or 'thinker' do not fully describe his role. Perhaps the term ‘reformer’ would best summarize his activities. One could say, with great simplification, that the purpose of his work was to change human nature. He was not concerned with the improvement of man's character, making him more cultured or tolerant. He tried to achieve something far more profound and significant - a total change of man's psyche, a change of his opinion of himself and his outlook upon life. This book is an introduction to Gurdjieff's teaching and presents his main theories, his methods of personal development and his biography. My objective was to write a book that presents the most important aspects of Gurdjieff's teaching in a simple and logical way, enabling the average reader interested in this field to comprehend its contents without referring to any other texts. The second objective of the book is to show the reader the relevance of Gurdjieff's teaching to contemporary society by explaining the origins of some of the problems faced by modern man. The book is aimed at people who ask perennial questions such as, ‘What is man like?’, ‘Why he is like that?’, and ‘What is the purpose of life?’