Microbiology usually only refers to the study of prokaryotic organisms: Bacteria and Archaea. This disposition does not do justice to the enormous diversity of unicellular eukaryotes (= protists), and their direct multicellular descendants, the seaweeds. These organisms encompass an evolutionary and functional diversity which far exceeds that of plants, animals or Fungi, and play a crucial yet understudied (and hence undervalued) role in ecosystems. The organisms which will be dealt with in this book range from minute to super-sized and include some well-known examples such as Euglena,...