We propose an object-oriented approach to the development of distributed applications emphasizing separation of concerns. Our approach combines the needs of transparency, encapsulation of distribution issues, and support for non-traditional models, where cooperation and sharing are desired. The development process is constructive, thus allowing partial verification of results. We recognize seven concerns: fragmentation, replication, naming, concurrency, failure, configuration, and communication. Each concern is perceived in three levels of abstraction: model, policy and mechanism. We also propose an integration process centered on development stages. Both concerns and stage perspectives are part of an integrated and flexible development process.