There is a "kingdom of plants," there is a "kingdom of animals." They have been known for a long time. In 1892, a graduate of St. Petersburg University D. Ivanovsky discovered another "kingdom" - viral. Now the attention of many sciences is riveted on him. These smallest particles of the substance, which, according to the authors of the book, have all the main signs of the living, accompany us from the day of birth, on their "conscience" more than half of all diseases.