The volume presents current views on the achievements made in the study of Systemic Functional Linguistics in both theory and application, and on the potential domains and directions for its further development. The first part addresses issues on strengthening theoretical research and description in system network, on deepening our understanding of the concept of choice and of consequences arising from making choices in particular social contexts. It also makes comparisons of different models within SFL and if similarities and differences between SFL and another linguistic model. Part Two deals with issues on further developing SFL as an applicable linguistics. After summing up its fifty years of refinement as a theory through constant endeavours of application, the volume offers an explicit definition of Applicable Discourse Analysis, and presents views on the potential areas, methods and criteria for verbal and multimodal discourse analysis, with examples. The final part of the volume discusses potential directions for SFL, including expanding SFL typological research into other languages than English, an in other countries than the major English speaking ones, exploring solutions to the challenges faced by multimodal discourse, extending traditional translation studies to other modes, making stylistics studies across different disciplines, exploring the potential of SFL to tackle the challenges confronting language education at both macro and micro levels, and seeking the road of globalizing SFL by developing an ideal software and establishing a global cyberspace institution.