A content-based publish/subscribe system for providing gapless message delivery from a publishing client to a subscribing client, the system includes a plurality of brokers operatively coupled to one another via a network. Each of the brokers include at least one processor and are configured as a publisher-hosting broker, a subscriber-hosting broker or an intermediate broker. The subscriber-hosting broker is operatively coupled to the publisher-hosting broker via the network through the intermediate broker. At least a portion of the plurality of brokers are configured so as to eliminate a need for persistent storage of messages at the intermediate broker and to substantially guarantee a gapless delivery of one or more messages transmitted by the publishing client to the subscribing client, even in the presence of a failure in the publish/subscribe system.