Brief introduction to tilings / Marjorie Senechal -- Tilings and quasicrystals: a non-local growth problem? / R. Penrose -- Group theory of icosohedral quasicrystals / P. Kramer and R.W. Haase -- Some local properties of the three-dimensional Penrose tilings / Andre Katz -- Defects in quasicrystals / J. Bohsung and H.-R. Trebin.