Softwood and hardwood lumber has, for the most part, largely been dried using empirically derived schedules, i.e., on a trial and error basis. These schedules are applied to the kiln through manual-set controller-recorders, which are non-reactive. That is, they do not respond automatically, schedule wise, to changes in the drying characteristics of the charge. Such schedules represent a combination of discrete changes in dry and wet-bulb temperatures and can be termed step-form type schedules. In hardwood drying where the use of kiln samples is much more common, the schedules might be viewed as semi-reactive since the predetermined step-form schedules are changed in response to the periodic measurement of the kiln sample's moisture content. In recent years there has been an increased interest in using schedules that continually change with respect to time or continuous change schedules. The ideal case would consist of a fully reactive control system capable of sensing the charge drying rate and/or quality and which would change the schedule in a continuous fashion. The various types of possible lumber drying schedules are summarized in Table 1. Cam controllers which are presently used in a number of kilns are non-reactive but permit the schedule to be changed on a continuous basis. A problem that we have observed when operations first begin using cam controllers and which is true for any other continuous change control system is how to develop a suitable schedule.