A comprehensive software package, called ANALYZE, which permits detailed investigation and evaluation of 3-D and 4-D biomedical images is described. This software can be used with any 3-D imaging modality, including X-ray computed tomography, radionuclide emission tomography, ultrasound tomography, magnetic resonance imaging, and both light and electron microscopy. The package is powerful in its synergistic integration of fully interactive modules for direct display, manipulation, and measurement of multidimensional image data. Several original algorithms that improve image display efficiency and quality are included. One of these is a versatile and powerful volume rendering algorithm. The inclusion of a variety of editing, quantitative mensuration, and macro design tools significantly extends the usefulness of the software., ANALYZE runs on standard Unix computers without special-purpose hardware.