Speculative service implies that a client’s request for a document is serviced by sending, in addition to the document requested, a number of other documents (or pointers thereto) that the server speculates will be requested by the client in the near future. This speculation is based on statistical information that the server maintains for each document it serves. The notion of speculative service is analogous to prefetching, which is used to improve cache performance in distributed/parallel shared memory systems, with the exception that servers (not clients) control when and what to prefetch. Using extensive trace simulations based on the logs of our departmental HTTP server ht tp: //es-wv. bu. edu, we show that both server load and service time could be re duced considerably, if speculative service is used. This is above and beyond what is currently achievable using clientside caching  and server-side dkzemination . We ‘identify a number of parameters that could be used to fine-tune the level of server speculation and we discuss variations of speculative service that involve cooperation with clients.