In following issue of „Progress in Medicine” we present the first part of the monography describing the problem of obesity and possibilities of its treatment. Currently, obesity is becoming huge health and socio-economic problem in Poland and worldwide. It concerns approximately 6 billion people (13% of world population, 11% men and 15% women) which was the main cause for preparation of this monography. Obesity is caused by accumulation of body mass due to positive energetic balance.

The causes of its epidemic are complex. Many of them are described by the term “environment in favor for obesity” and include society structure, economic policy, socio-economic development, genetic predispositions to obesity. The research on the monogenic and poligenic type of obesity as well as on the significance of association studies on the whole genom (GWAS) are still in progress. Those issues have been developed in articles “Epidemiology and pathogenesis of obesity” as well as “Genetics in obesity”.

According to global epidemic of obesity, bariatric-metabolic surgery has become one of the most rapidly developing areas in surgery in 20^th and 21^th century. Although, the origins of bariatric surgery are in USA and countries of Western Europe, in 1950s the number of conducted procedures was insufficient. In 1980s and 1990s the discipline rapidly developed all over the world. Currently, 500 000 procedures are performed including 2000 in Poland.