Turbo codes and their relatives, especially LDPC codes, have been established to be extraordinarily effective on the AWGN, binary erasure, binary symmetric, and a few other standard channel models. Indeed, for these channels, Shannon's Problem (the problem of communicating reliably and practically at rates close to channel capacity) has now been solved.

But Shannon's coding theorem tells us that reliable communication at rates near capacity is possible on any channel, not just the AWGN, BEC, and the the BSC,. From this viewpoint, Shannon's Problem has barely been touched. We believe, however, that the ``turbolike'' codes mentioned above (together with the associated iterative decoding algorithms) can be used, after suitable modifications, to solve Shannon's Problem on virtually any channel. In this talk, I will discuss the potential and actual effectiveness of turbolike codes on a variety of "nonstandard" (memoryless) channel models, including symmetric and nonsymmetric binary and nonbinary input channels.