This is a one year Planning Grant to a young Principal Investigator at the University of Guam to conduct numerical simulations of tilted accretion disks in models of pulsar binary systems. The aim of this project is to bring together high energy (x- and gamma- ray) and optical observations to attempt to discriminate among competing theories of the "long periods" of x-ray pulsar binary systems, such as precisions of tilted disks and obscurations of the pulsar emission by clumps in the disks.