Abstract. As the ever-growing Internet applications in the emerging e-societyare centered in sharing of various types of digital contents, content delivery onthe Internet as a hot topic has been attracting most attentions. Web caching is animportant technology for improving the efficiency of content delivery. As anemerging technology en-route caching computes locations among caches on accesspaths to store copies of an object such that specified objectives (such assatisfying future access demands to the object) are achieved. In this talk, I willfirst give an overview on recent developments in efficient content delivery. Iwill then introduce our recent work in tackling this problem by applying thetechnique of en-route caching, and present efficient solutions to the problem insystems containing single server and multiple servers respectively. While theproblem is NP-hard in the general case, our solutions apply dynamic programmingtechnique and run in polynomial-time in the worst case for both unconstrainedand constrained cases in the network topologies of trees (for broadcastdelivery) and linear arrays (for point-to-point delivery) respectively. They areshown theoretically either optimal or convergent to optimal. Finally, I willshow some possible extensions of our solutions to other system settings.