Compositional data and their analysis: an introduction, V Pawlowsky-Glahn and J J Egozcue • Applications to the solution of real geological problems • Major-oxide compositional discrimination in Cenozoic volcanites of Hungary, L Ó Kovács, G P Kovács, J A Martín-Fernández and C Barceló-Vidal • Log-ratios and geochemical discrimination of Scottish Dalradian limestones: a case study, C W Thomas and J Aitchison • Discriminating geodynamical regimes of tin ore formation using trace element composition of cassiterite: the Sikhote'Alin case (Far Eastern Russia), N Gorelikova, R Tolosana-Delgado, V Pawlowsky-Glahn, A Khanchuk and V Gonevchuk • On stability of compositional canonical variate vector components, R A Reyment • Compositional changes in a fumarolic field, Vulcano Island, Italy: a statistical case study, A Buccianti, F Tassi and O Vaselli • Ternary sandstone composition and provenance: an evaluation of the 'Dickinson model', G J Weltje • Software and related issues • Detailed guide of CoDaPack: a freeware compositional software, S Thió-Henestrosa and J A Martín-Fernández • Compositional data analysis with 'R' and the package 'compositions', K G van der Boogaart and R Tolosana-Delgado • Visualization of three- and four- part (sub)compositions with 'R', M Bren and V Batagelj • General theory and methods • Simplicial geometry for compositional data, J J Egozcue and V Pawlowsky-Glahn • Exploratory compositional data analysis, J Daunis-i-Estadella, C Barceló-Vidal and A Buccianti • Frequency distributions and natural laws in geochemistry, A Buccianti, G Mateu-Figueras and V Pawlowsky-Glahn • Rounded zeros: some practical aspects for compositional data, J A Martìn-Fernandez and S Thió-Henestrosa • Is the simplex open or closed? (some topological concepts), E Barrabés and G Mateu-Figueras