A microcomputer-based facility is described that permits the data required for three-dimensional reconstructions to be collected quickly and inexpensively from serial sections. The facility consists of a microcomputer, a digitizer tablet, a graphics terminal, a printer, a plotter, and telephone coupler. Images of serial sections are superimposed on the digitizer tablet. Contours of interest on each section are digitized and the coordinates are stored on “floppy” disks. The problems of putting successive sections in correct register and of taking into account magnification factors are discussed briefly. Use of the facility for high-resolution applications is also considered.