Olson's poetry: an attempt to grasp the history of human thought, The Maximus Poems, by Charles Olson. Edited by George F. Butterick. Berkeley, Calif.: University of California Press. 658 pp. $35.

It is impossible to describe in this small space the immensity of Charles Olson's achievement - as poet, theoretician, and explorer of the ''human universe.'' Just as Ezra Pound's writing energized Western poetry in the first half of this century, Olson in the 1950s redefined its direction and inspired the next generations of writers. His essay ''Projective Verse'' consolidated the principles of ''open verse'' and charged it with new goals and responsibilities. His premise was that the essential harmonies and tensions in a poem do not arise from predetermined form and meter. Instead, Olson directed poets to the ear's measure of language, the syllable; and the natural timing of speech, the breath. ''The Maximus Poems'' represented 20 years of work; long out of print, they are now published in a complete edition for the first time. Like Pound's ''Cantos,'' ''The Maximus Poems'' are a complex far-ranging attempt to grasp the history of human thought. But Olson grounds his book more firmly in the songs and letters of a mythical figure, Maximus, and the seascape of Gloucester, Mass. Here is the last section from ''Letter 9.'' 4 I measure my song. measure the sources of my song, measure me, measure my forces

(And I buzz, as the bee does, who's missed the plum tree, and gone and got himself caught in my window

And the whirring of whose wings blots out the rattle of my machine)