In the article an attempt is made to systematize the information we have on the special epistolary genre (genre of «letter to a ruler») is available. «Letter to a ruler» is a letter of the Russian intelligentsia to power (we limited ourselves by the study of the writersʼ letters). «Letter to a ruler» is represented by two invariants – «letter to the tsar» (the 19th – the beginning of the 20th century) and «letter to the leader» (the 20th century). Analyzed letters can be viewed in the context of writer’s biography, in context of Russian history and as special epistolary genre with its own distinctive characteristics and modifications. Listing specific evidence, we excrete in the «letter to ruler» several varieties of the genre (letter-invective, letter-declaration, letter-pamphlet, letter-complaint / request / justification letter-praises / gratitude / creative report), trace qualitative and quantitative dynamics of development of each species, as well as provide a brief summary of my observations over the addressee of letters.