Diversity and Ecology -- A New Extreme Environment for Aerobic Anoxygenic Phototrophs: Biological Soil Crusts -- The Phototrophic Consortium "Chlorochromatium aggregatum" - A Model for Bacterial Heterologous Multicellularity -- The Ecology of Nitrogen Fixation in Cyanobacterial Mats -- Physiology, Metabolism, and Global Responses -- Nitrogen and Molybdenum Control of Nitrogen Fixation in the Phototrophic Bacterium Rhodobacter capsulatus -- The Network of PII Signalling Protein Interactions in Unicellular Cyanobacteria -- Pathway and Importance of Photorespiratory 2-Phosphoglycolate Metabolism in Cyanobacteria -- Beyond the Genome: Functional Studies of Phototrophic Sulfur Oxidation -- Multicellularity in a Heterocyst-Forming Cyanobacterium: Pathways for Intercellular Communication -- Bioenergetics, Proteins, and Genomics -- The Photoactive Orange Carotenoid Protein and Photoprotection in Cyanobacteria -- Proteomic Analysis of the Developing Intracytoplasmic Membrane in Rhodobacter sphaeroides During Adaptation to Low Light Intensity -- A Glimpse into the Proteome of Phototrophic Bacterium Rhodobacter capsulatus -- Phycobiliprotein Biosynthesis in Cyanobacteria: Structure and Function of Enzymes Involved in Post-translational Modification -- The Tetrapyrrole Biosynthetic Pathway and Its Regulation in Rhodobacter capsulatus -- Environmental Sensing and Signal Transduction -- The Gene Transfer Agent of Rhodobacter capsulatus -- Integrative Control of Carbon, Nitrogen, Hydrogen, and Sulfur Metabolism: The Central Role of the Calvin-Benson-Bassham Cycle -- Applied Aspects -- Better Living Through Cyanothece - Unicellular Diazotrophic Cyanobacteria with Highly Versatile Metabolic Systems -- A Feasibility Study of Large-Scale Photobiological Hydrogen Production Utilizing Mariculture-Raised Cyanobacteria -- Hydrogenases and Hydrogen Metabolism in Photosynthetic Prokaryotes. ISPP2009, the 13th International Symposium on Phototrophic Prokaryotes, was held in Montreal, Canada, from August 9 to August 14. This was only the second time that the ISPP series was in North America. ISPP2009 was well attended with about 280 registered participants from over 30 countries. A stimulating and inf- mative program showcased the recent developments in this ever-evolving eld. This is always one of my favourite conference series to attend because not only does it inform my speci c research passions, it broadly educates me in ways that improve my teaching and increase my breadth of understanding in a variety of outside areas. Indeed, the ISPP series brings together a broad spectrum of interests, techniques, and disciplines. Both established researchers and newcomers to this eld gave oral presentations in a large number (80) of plenary and parallel symposia sessions which proved to have active audience participation and lively discussions. A large number of excellent poster presentations supplemented the oral program. I think that the high quality of the scienti c presentations, as well as the enjoyable social events, was widely appreciated. Things ran very smoothly, from the original registration to the closing ceremony, thanks to Isabel Stengler and her team at IS Event Solutions.