This monograph presents the results of many years research devoted to the development of complex biotechnological systems of creation the new forms and clonal micropropagation of such essential oil plants as lavender (Lavandula angustifolia Mill.), sage (Salvia sclarea L.), coriander (Coriandrum sativum L.), fennel (Foeniculum vulgare Mill.), anise (Anisum vulgare Gaerth.), yarrow (Achillea spp.), essential oil rose (Rosa spp.) and geranium (Pelargonium spp.). These biotechnologies are based on the investigation of features of isolated organs, callus tissues cultivation and morphogenesis induction in vitro. Chapter I deals with the general information on the methods of cell engineering that allow creating new plant genotypes and propagating them in vitro. The following Chapters summarize biotechnological research carried out at the Research Institute of Agriculture of Crimea (the former the Institute of Essential Oil and Medicinal Plants), using aromatic plant species, mainly grown in southern Russia (lavender, coriander, sage, fennel, rose yarrow etc.). The conditions of callus cultures obtaining from different explants were optimized and peculiarities of exogenous and endogenous factors effects on the callusogenesis efficiency of studied essential oil plants were detected. The methods of plant regeneration from calluses of different passages for more than fifty cultivars and samples of lavender, sage, coriander, fennel, anise, geranium, yarrow have been developed. The peculiarities of genotype, hormonal composition of culture medium, type of explant and number of passage influence on the morphogenesis induction have been determined. The means, 6 which permit to increase the frequency of organogenesis and somatic embryogenesis of callus cultures and to regenerate the plants during 1-3 years, were revealed. Furthermore, the method for creating essential oil rose hybrids using embryo culture and clonal micropropagation in vitro was developed. The peculiarities of abiotic stress factors effect at different biotechnological objects (calluses with and without morphogenesis and zygotic embryos) have been revealed. For the first time, the selective systems in vitro for screening forms with resistance to salinity, osmotic and low temperature stress have been elaborated for lavender, sage, geranium, coriander. For lavender, geranium, yarrow, fennel, rose and sage, methods of clonal micropropagation have also been created. The influence of cultivar, medium composition, explant disposition on the shoot and number of subcultivations on the propagation efficiency was shown. Based on the analysis of the regenerants from lavender, sage, geranium, coriander, yarrow and fennel calluses, the somaclonal variability by morphology and economic valuable characteristics have been determined, and prospects for breeding forms have been revealed. One of the practical results of these scientific studies is a new cultivar of clary sage Selinzh, which was created using somaclonal variants.