For his innovative use of the confocal laser-scanning microscope to obtain three-dimensional images in cell biology Nils Åslund (b. 1931) has had biomedical image physics, and fluorescence microscopy in particular, as his research field. His use of the confocal laser-scanning microscope to obtain three-dimensional images in cell biology helped to make confocal microscopy the powerful tool in biomedical research that it is today. Projects carried out by Åslund and his research group, combining laser scanning with confocal imaging, have involved collecting digital stacks of images for three-dimensional visualization and analysis. Åslund has also developed instruments and data-processing methods. Key concepts in his work are the “term value method” in molecular spectroscopy, IRIS and OSIRIS scanners in imaging technology and the “histostack” method in 3D densimetry. More information: www.imagesinscience.com/kap5.html