An increasing number of new and more sophisticated quantitative analyses forces biologists to find an adequate statistical software. In our opinion free software R is the best solution for many types of ecological and other biological analyses. R software provides tools for effective data handling, modern statistical methods and excellent graphic facilities. In our paper we introduce R, discuss benefits of the program and briefly comment several R packages appropriate for biologist. In the next articles of the series about R we will try to illustrate the usage of particular R packages or statistical methods on real data examples