In this chapter, we have shown how to eliminate costly global synchronizations from the multicomputer implementation of explicitly parallel constructs like the FORALL construct. Global synchronizations can be eliminated from the implementation of many static communication patterns using dependence analysis. Other communication patterns may be effectively classified as reader unknown and writer unknown patterns. Global synchronization can be eliminated from reader unknown patterns using definition variables. Results show that the definition variable implementation is significantly better than a barrier implementation, especially for sparse communication patterns with high effective gaps. We have not eliminated global synchronization from writer unknown patterns. The essential problem in writer unknown patterns is that an unknown remote thread may write the data element owned by a given thread. The data element cannot be implemented using definition variables, since it is not known whether the element will actually be written (if it is not written, the definition variable would hold requests forever and cause deadlock). If there is a guarantee that the element will or will not be written, then definition variables can be used, and global synchronization can be removed. Hence, only a very small set of writer unknown dynamic communication patterns need global synchronization.