A minimum of 30 minutes is required to learn even the rudiments of the command language (Symbolic Language). Although written instructions are helpful, practice is essential. The programmed instruction routines, which took approximately 20 minutes, were mostly of the 'yes-no' variety. Expanded routines, which would require other replies and would give student-users actual practice in formation of retrieval requests would have been better, but would have taken considerably more time (and would have tried the patience of more astute students). Flexibility was sacrificed for the sake of simplicity in the command language, and this was pointed out as a definite deficiency by many of the subjects. Increased flexibility would have added to the required learning time. The slow typing speed of the teletypewriter (slower than the average reading rate) and the high noise level were pointed out as distracting factors by many of the subjects. (Author)