A scanning laser microscope (SLM) has been constructed for use in imaging single living skeletal muscle fibers. The muscle fiber is kept alive and stimulated in a temperature-controlled chamber through which a nutrient solution flows. The fiber is attached at each end to force and displacement transducers which are in turn connected to electromagnetic (voice-coil type) linear motors. These motors scan the fiber in one axis (x-axis) and are also used to stretch and shorten the fiber during mechanical experiments. Each of the x-axis linear motors is in turn mounted on a micro-stepping motor which provides for rotation (r-axis) and twist of the muscle fiber. A laser beam is focused at a location within the fiber by high numerical aperture confocal optics which form one path of a mach-Zehnder interferometer. The position of the muscle fiber with respect to the laser beam may be further manipulated by two additional electromagnetic linear motors (y-and z-axis) to permit 3-linear and 1-rotary axis scanning. The scanning pattern is controlled by a Micro-VAX-II computer which is also used to sample the output of the photo-detector and the force and displacement transducers. A complex 3-D image is acquired and processed (e.g. SLM optical transfer function identification and deconvolution) on the VAX using NEXUS-plus a language for linear and nonlinear signal and system analysis.