This volume provides the first detailed diatom identification guide for the Maritime Antarctic region. All taxa found during a large taxonomic and ecological freshwater diatom survey on the South Shetland Islands and James Ross Island are included. Taxa are listed following the systematic classification of Round et al. (1990) and further alphabetically within each genus. Each taxon is discussed on a single page providing the following data: the original reference; a morphological description based on LM and SEM observations; a comparison with similar taxa; data on its ecology (where available). Per taxon, an entire plate composed of high quality LM and SEM micrographs is shown, illustrating all morphological details. The last plates contain unidentified taxa for which, due to their rarity in the samples, insufficient observations were made and hence formal description / identification is not possible. Short descriptions giving morphometric details are added for these taxa. The appendix at the end of the volume contains confirmed distribution records for each taxon & a list of all taxonomic papers that have been published since the start of this survey by the book authors on Maritime Antarctic diatoms.