With wireless communications and mobile hand-held devices becoming a reality, new applications where users can have access to information anytime, anywhere are made possible. To design a middleware-based platform for applications such as emergency aid, crisis managements, our approach is threefold. We design and implement a middleware platform that hides as much as possible the details of the hardware, the operating system, and the telecommunication protocols from application developers and users. Then, we define a context manager associated with a middleware manager that cope with the collaboration between the users and the other middleware services. Next, users and the other middleware services rely on context information: the former for expressing needs and behaviour, the latter for being pro-active. These middleware services include disconnection management, fault management, deployment. KEY WORDS Proactiveness, mobile environment, context-awareness, disconnection management, faul...