Exploring matter with Neutrons explains neutrons and the unique properties that make them so useful to science and industry. The experimental instruments and the large array of neutron applications in the most advanced fields of physics, chemistry, biology, and materials science are described in an interactive manner. The encyclopedia is destined for students, teachers, research institutes, industry and the general public interested in these topics. The multiple-entry points permit each and every visitor to explore the CD-ROM according to their own knowledge and curiosity. Both 2D and 3D animations, and virtual reconstruction with computer-generated images are used to guide visitors through this scientific and technical world, helping to make it both understandable and exciting. Exploring matter with Neutrons encyclopedia is the outcome of a very tight collaboration with the international consortium formed by the most prestigious neutron institutions: Institut Laue-Langevin, France; Los Alamos Neutron Science Center, USA; ISIS Pulsed Neutron & Muon Source, Great Britain; GKSS Forschungszentrum, Germany; Forschungszentrum Jülich, Germany; Hahn Meitner Institut, Germany; Laboratoire Leon Brillouin (CEA-CNRS), France. Topics from the content: Neutron Sources: Natural sources. Transportable sources. High flux sources. Next generation sources. Science: Neutrons and states of matter. Magnetism. Materials. Tools for neutron science: Transmission imaging. Diffraction. Small-angle scattering. Reflectometry. Inelastic scattering. Quasielastic scattering. Spin echo. Recoil and gamma spectrometry. Applications - Fundamental Research: Fundamental physics. Structural biology. Solid state chemistry. Magnetism. - Applied Research: Metallurgy and materials. Chemistry. Earth, planets, meteorites.