Over the course of history, humankind has relied on the power of language to impose regularities on experience and bring "the environment more within our power to control." Professor M.A.K. Halliday goes on to refers to this conceptual shifting as "the Knight's move in language."

In this joint work, developed in collaboration with the late Professor Ruqaiya Hasan and edited by Professor Jonathan J. Webster, metaphor is used to understand how language manipulates and creates our reality in very real and powerful ways. Whether it is the "art" in verbal art or the "science” in verbal science, through the metaphor-making potential available in language what is being crafted are hypotheses about the world we experience. The semiogenic power of language is so great that it enables us to define "the very basic experience of being human". Halliday adopts Mukarovsky's term "deautomatization" to interpret the grammar in front of you in ways that go beyond its direct relational function.

So much scientific theory would not be possible without this semiogenic potential. It is the ability to reconstrue our commonsense version of events into a metaphorical world where things can be observed, investigated and explained. This book highlights the central importance of grammatical metaphor and realigns the connections between the upper strata of meaning and the strata below lexicogrammar.