I wrote this book for biologists and those who are interested in both biological affairs in general and perspectives which integrate a large number of specialised biological disciplines. The theory of biocommunication presented herein investigates signal transduc- tion processes among cells, tissues, organs and organisms in bacteria, animals (corals and bees), fungi and plants in the light of the current available empirical data. Because life is the central focus of the life sciences, this theory will also focus on typical features of life as opposed to inorganic matter.