Yukaghir birch bark letters have been known to science for over a hundred years. It all began in 1889, when a student at Novorossiysk University was convicted of revolutionary activity and exiled to the distant Yakutsk region. For several years, he lived alone among the Yukaghirs, one of the indigenous peoples of the North, and discovered that the local population used "writings on birch bark." Samuil Shargorodsky published a short article in the journal "Zemlevedenie" in which several Yukaghir toses were described for the first time (tos in Yukaghir means birch bark). Since then, the number of toses introduced into scientific circulation has gradually increased. This book is the first complete collection of all known toses, including those discovered in the last 30 years and never published before. Among the toses, which served to transmit written information over a distance and in time, two types stand out: "male" and "female." "Male" tosas were maps of the area or hunting route diagrams, while "female" tosas were love notes from young unmarried girls to young men, describing feelings, past or future events and relationships. If the first type of letters has analogies in Siberia and North America, then the second is apparently unique on a global scale. In his research, the famous Russian scientist and northerner, professor at the European University in St. Petersburg Nikolai Vakhtin talks about the rules for reading tosas and the semantics of their individual signs, discusses the place tosas occupy among other pictographic systems, how ancient this phenomenon is and what it represents from the point of view of writing theory.