This Element tries to discern the known unknowns in the field of pragmatics, the 'Dark Matter' of the title. We can identify a key bottleneck in human communication, the sheer limitation on the speed of speech encoding: pragmatics occupies the niche nestled between slow speech encoding and fast comprehension. Pragmatic strategies are tricks for evading this tight encoding bottleneck by meaning more than you say. Five such tricks are reviewed, which are all domains where we have made considerable progress. We can then ask for each of these areas, where have we neglected to push the frontier forward? These are the known unknowns of pragmatics, key areas, and topics for future research. The Element thus offers a brief review of some central areas of pragmatics, and a survey of targets for future research. This title is also available as Open Access on Cambridge Core.