Papers were presented at ISTRY-2006 Toyko under such headings as 'Updates on Chemistry of Indoles and Aromatic Metabolites Therefrom', 'The Bis-indole Indirubins: From Indigo Plant to Clinic', 'Systematic Tryptophan Depletion', 'Biochemistry and Molecular Biology of Tryptophan Metabolism' and 'Analytical Chemistry'.