SLN (Simulation of Logical Networks) is a new simulation language designed specifically to provide concepts and facilities needed to model and simulate logical networks. Logical networks provide a convenient and natural means of expressing decision processes when a general-purpose discrete-event simulation facil ity is unnecessary. SLN accepts a node and branch description of a logical network and automatically handles the construction and execution of the simulation. FORTRAN can be mixed with the SLN statements with few restrictions. SLN is highly efficient, simulating only logical networks and working as a preprocessor generating FORTRAN source which can be compiled, linked, and executed. The SLN library includes facilities for generating random variates, collecting and reporting statistics, monitoring simulation execution, and tailoring the simulation output. SLN is portable and designed for use in an environment lacking a modeling tradition.