This publication contains the user's guide to the EPA Atomic Absorption Instrument Automation System. This system can receive lists of samples from the Sample File Control System and return the measured concentrations to that system. It is capable of interfacing with a number of commercially available atomic absorption instruments. It incorporates the following major features: (1) multi-point calibration using first, second, or third degree regression or linear interpolation, (2) timely quality control assessments for spiked samples, duplicates, laboratory control standards, reagent blanks, and instrument check standards, (3) reagent blank subtraction, and (4) plotting of calibration curves and raw data peaks. The programs of this system are written in Data General Extended BASIC, Revision 4.3, as enhanced for multi-user, real-time data acquisition. They run in a Data General Nova 840 minicomputer under the operating system RDOS, Revision 6.2. This document contains detailed descriptions and examples of the features of the system, as they appear to the user. Two related publications are 'The Standard Calibration Instrument Automation System for the Atomic Absorption Spectrophotometer Part I - Functional Specifications' and 'The Standard Calibration Instrument Automation System for the Atomic Absorption Spectrophotometer Part III - Program Documentation.'