This application proposes to finish development of a method of monitoring and recording the pulmonary function of asthmatic and other pulmonary patients. Prototypes in Phase I successfully demonstrated the feasibility of such devices. The device measures the pulmonary peak flow. It displays the results instantaneously on an LCD screen. The unique capacity of this device is its ability to record the actual measured peak flow together with the date and time of each measurement over a four month period. This complete record of pulmonary status across time can then by retrieved by the patient's physician to aid in clinical decision-making. Phase I of this proposal was a feasibility study. In Phase II Forefront's specific aims to: 1. Complete the design of the Peak Flow device, 2. Complete the design and implentation of the interpreter software which retrieves data from the Peak Flow device and presents data analysis, 3. Design and build 200 units for study, 4. Validate the performance of these units with internal testing, and most importantly, 5. Validate the clinical significance with a two center study using the 200 units. This device will have significant applications for physicians interested in tracking patients' peak flow measurements across time without requiring daily record keeping by patients. In addition, this device could be used as both a clinical and a research tool in the study of bronchodilator efficacy in home settings. The hope is that it may be utilized to improve the treatment of asthma.