Dimitar Krustev entered the office of The Echo with an energetic step and a plastic cup of cold tea in his hand. One could not say that the short man dressed in a black T-shirt and jeans had turned 41 in July. His blue eyes were full of vitality and the desire to share.

It is difficult to give a short definition of who Krustev is, because in his life he has been a driver, lifeguard, postman, presenter at the Bulgarian National Radio and the National Television, dubbed foreign films (mainly documentaries), and has participated in pantomime performances.

Apart from these occupations, Krustev has always taken pleasure in Eastern philosophies, martial arts, massage and healing gymnastics. He is the founder of the Duonika system which aims at helping people live their lives in a better way. As a method of promoting this system, he organized and took part in a "solo swimming marathon" last summer. On August 31 he is doing it again but this time not alone because his 50-year-old friend Ivan Stoev will join him in the running part of the marathon.

The system started in 1993, when Krustev went to study Esperanto in China. He met a Japanese massage teacher, learned the art of massaging and started practicing it. Upon his return to Bulgaria in 1994, he came up with the idea of his system and called it Duonika. The guide to Krustev's system was published in 1996 in a book called Duonika: The Winning Stratema of Living.

"The book of my life is a synthesis of physical, psychological and philosophical ideas aimed at helping people to solve the problems of their lives, how one can improve his or her life and deal with the problems which are the basis of human drama," Krustev explained.

The main idea of Duonika is that the winning formula of living is co-operation. The author said that in developing his system he has made corrections to some of the fundamental philosophical postulates which are popular in the region, in "our geographical and cultural zone." One is Hegel's popular dialectic about the unity and conflict of opposites which Krustev described as one of the pillars of the ideology of Marx and Engels. "The idea of the unity and conflict of opposites is one of the most serious delusions of our time," he pointed out. "My thesis is that the world is unity and co-operation of differences, not opposites. Therefore the world is so colourful."

According to Krustev, the idea of the unity and conflict of opposites leads to a black-and-white way of thinking. He referred to Lenin's idea of "If you are not with us, then you are against us."

"There is no room for abstainers, which is a characteristic of democracy," said Krustev. "This leads to totalitarianism and racism because he who is not white is black."

In preparing the system and the book Krustev read a lot of the writings of Freud and got to know many Eastern and mystic teachings. "I wrote it for the contemporary person," he said.

Duonika is not only a philosophical and psychological teaching but is also concerned with the physique. A substantial element of the system is the set of physical exercises performed in pairs and again based on the idea of the power of co-operation. "The exercises are always done with a partner because that is in the context of the theory," he said.

He has published another, smaller book which serves as an introductory and more practical reading. Krustev uses it as a guide during the three-day Duonika workshops he organizes. "Different people attend my seminars," the ideologist said. "Mainly middle aged, but there have also been some young people." The seminars, which always take place somewhere outside Sofia, focus on lectures, discussions and exercises.

There are five sets of exercises in Duonika - two for beginners - for indoors and outdoors, and for advanced parent-child pairs and husband-wife or girlfriend-boyfriend pairs.

Krustev explained that his system was closest to Tantra - the Hindu spiritual system written in Sanskrit and concerned with powerful ritual acts of body, speech, and mind. It was also very similar to some styles of marshal arts which are based on cooperation, such as aikido and tai chi.

"In my life, I strictly follow the principles of my theory," Krustev said. "Honestly, I do not always succeed to live successfully because I am a human being and, like all other human beings, I have to fight with inherited mental prejudices. Still, every time I have used these principles I have achieved spiritual harmony and have solved problems in a constructive way."

Krustev currently lives with his mother. He is not married but has been seeing a girl for the past 10 years. His swimming marathon last summer was on the occasion of his 40th birthday.

"Swimming is actually is a clear demonstration of cooperationa cooperation with the sea," he said. "This is a real making of love with the sea. Some people say that they love the sea and go to the seaside and get drunk, sleep until 10am, watch it from a distance, get their feet wet to the ankles and then go to continue their drinking. For me these people are voyeurs, they love to observe. However, one makes real love with the sea when he swims and enjoys it."

Last summer, Krustev began his marathon from the old town of Nessebar and swam north to the village of Vlas. "I swam about 3 nautical miles, which is about 5,555m," said the swimmer who finished the distance in an hour and a half. "I was working in Nessebar as a massagist at the time and was exercising at the beach every morning. While doing them I was looking at the shore of Vlas and decided to swim to there."

Krustev hopes that this summer other people will join him and his running partner. Despite being a solo swimmer, Krustev and his Duonika system do not lack supporters. "A group of followers join me every Sunday when we go to Vitosha mountain, perform some of the exercises, discuss life problems and try to find solutions."

No wonder Krustev describes himself as a problem-solver.