This collection is one of the summary works of the Polar-Alpine Botanical Garden of the Kola Branch of the Academy of Sciences of the USSR, named after S. M. Kirov, devoted to plant introduction and the greening of the Far North. The volume contains the results of introduction experiments conducted by the botanical garden over a period of twenty-five years, involving more than 3,500 plant species, including wild plants introduced from various geographical regions, plants undergoing domestication, and ancient cultivated plants, including horticultural varieties and hybrids. In the garden's earlier work, Introduction of Plants into the Polar North (N. A. Avrorin, 1956), a selective ecogeographical analysis of the behavior of introduced plants was carried out, and certain patterns of simple transplantation and acclimatization were revealed. All plants described in this volume were tested in open ground without any protective measures against the severe polar climate conditions, characterized by an eight-month winter, cool summers with frequent frosts, and the complete absence of nighttime darkness until early August. The experimental nursery of the botanical garden is located on the southern slope of Mount Vudyavrchorr in the Khibiny Mountains of the Kola Peninsula, at an elevation of 320-340 meters and more than 100 kilometers north of the Arctic Circle (67°39′ N). The plants recommended in this volume can undoubtedly be successfully cultivated throughout the forest and forest-tundra regions of Murmansk Oblast and Arkhangelsk Oblast, as well as in the Karelian Autonomous Soviet Socialist Republic and the Komi Autonomous Soviet Socialist Republic. They may also be suitable for the coastal areas of Magadan Oblast, Kamchatka Oblast, and Sakhalin Oblast. Naturally, they are equally suitable for regions farther south. For other, more severe areas of the Soviet Far North, suitable local forms for landscaping should be selected from among these plants through additional local testing. The material in this volume is arranged according to the most commonly used system: families follow the Engler classification system, while genera and species are listed in alphabetical order of their Latin names. The index at the end of the book is intended to facilitate the search for desired species. The work of T. G. Tamberg describes all species and varieties of beautiful annual and biennial flowering plants that she studied between 1947 and 1955, and supplements these with descriptions of most species tested by the botanical garden during earlier years (beginning in 1932). The work lists a total of 140 species and approximately 200 varieties, of which 94 species belonging to 18 families are recommended for practical use in northern landscaping. In the works of L. I. Katyulina and N. A. Avrorin, only those plants recommended for practical landscaping are described: 42 species of hardy shrubs belonging to 8 families and 90 species of perennial herbaceous plants belonging to 20 families. In addition, more than 60 other perennial species are briefly described or mentioned; although they can be cultivated, they are inferior in beauty or hardiness to the species described in greater detail. The article by V. K. Neofitova is the first to present information on diseases of ornamental plants in the North and the measures used to control them.