Owen Barfield's nature and achievement is usually under-sold by a partial, and therefore misleading, summary; that states Barfield's goal was to prove by evidence that human consciousness had evolved; and that this evidence was provided mainly via 'philological' investigations into the changing meaning of words.
Of course Barfield did this - but he did so much more, and this achievement served a much bigger purpose than usually realised.
The problem is that the above description sounds like an essentially academic type of activity - and therefore of interest mainly to academics - presumably those concerned with the meanings of words.
But in fact; Barfield was writing for everybody and for all time - and his core concern was nothing less than the divine destiny of each individual person and of all people collectively.
Barfield's immediate relevance is profound; it is to solve the core problem of modern times - which is 'alienation': i.e. the deep sense of meaninglessness, purposelessness, and isolation from people and things.
The understanding which makes this possible is that history, the present and the future can be understood as aiming-at both consciousness and freedom (where consciousness means awareness of our thinking and our selves, and freedom refers to free will, or human agency).
Barfield's scheme is that humans began as conscious-but-not-free; and we evolved - evolved in the sense of changing by unfolding according to a (divine) developmental plan - to become free but not conscious (which is where we are now, in modern times - unaware of meaning, purpose, relation) - and we ought-to-be aiming at the condition where we are both self-aware and fully-conscious - engaged with (and participating-in) reality as free agents.
Even more briefly, humanity began as conscious, became free; and is destined to become both - simultaneously.
So Barfield 'in a nutshell' is so much more than a scientist-philosopher of language and its change; he is a thinker about the most fundamental problems.
And Barfield is not merely an analyst of problems: he proposes real, coherent, and clear answers to these most fundamental problems.