This work is a result of 40 years of research, mainly by the authors, on wild relatives of seven important cool season legumes. The primary aim of this research was to identifying the potential of wild relatives of these legumes for breeding purposes. Studying the wild relatives of cool season legumes includes evaluation of their taxonomic status, their morphological variation, ecological requirements, exploration of their distribution, and seed collection in their natural habitats. These seeds were used for examining their protein profile as preliminary hints of their affinity to the cultigens. Plants grown from these seeds were used for establishing their karyotype, producing intra- and interspecific hybrids and analyses of their chromosome pairing at meiosis and fertility. The aim of these investigations was the identification of the potential wild gene pool of the domesticated forms. Assessment of genetic variation among accessions, particularly in the genus Lens, was made by isozymes and chloroplast DNA studies.