Rosanna Warren at Salmagundi:
Robert Lowell is, for me, the inescapable elder poet, and Day by Day is the inescapable book. It is where you go if you want to see where American poetry last set into major balance an art fully aware of its traditions and an experimental openness to unliterary raw material. Leaving behind the ruck and rubble of Notebook and History, it steps beyond the Cyclopean masonry blocks of the unrhymed sonnets of The Dolphin and ventures into irregular but adamantine shapes of feeling and thought. The smashed sonnets may suggest the smashed life or lives the book loosely recounts: aging friends, dead friends, dead parents, are summoned; a marriage is chronicled in its dilapidations; mental breakdown sends the suffering speaker once again to a hospital. From these wreckages and from the wreck of stricter verse form, Lowell has saved the aphoristic essentials, and broken through to poetic renewal in the very recognition of failure. Sacrifice, truly executed, earns recompense, and these poems do.
more here.