In 1984, three years after Bon Iver’s Justin Vernon was born, Dr. Norman Rosenthal of the National Institute of Mental Health first introduced the public to the concept of Seasonal Affective Disorder. Known commonly by the often-appropriate acronym SAD, the disorder is essentially a form of depression triggered by the changing of the seasons. It feels a bit disingenuous to draw too direct a corollary here, but Vernon has certainly made no secret of his fascination with seasons and sadness.

Prior to Bon Iver’s latest record, the band’s three releases thus far have each taken a different season as their unofficial inspiration. 2007’s acclaimed “For Emma, Forever Ago” was a folk ode to winter — famously written in a cabin, deep in rural Wisconsin, during the cold season — while the group’s eponymous 2011 album featured a lusher sound that aptly paralleled the arrival of spring. In 2016, Vernon returned with the experimental “22, A Million” – a record full of strange textures that reframed Bon Iver’s image from generously bearded mountain man to renowned electro-pop illusionist.

With “i,i” – which arrived early, in digital form, on Aug. 8, but is release physically today – the cycle of seasons is complete. If Bon Iver’s third album was an expansion in sound, then “i,i” represents a return the more disjointed, eerily beautiful isolation Vernon so adeptly conjured on the band’s first two records. The result is an album that leans closer to Vernon’s earlier work but could not exist without “22, A Million” as its precursor.

Often presented as emotional puzzles without definitive answers, Bon Iver’s earlier work situated Vernon’s voice as a featured instrument in a faceless orchestra. While the familiar sounds that have long permeated Bon Iver’s world remain – acoustic strums, dissonant reverb, and fragmented, haunting vocals – the difference this time is the focus paid to Vernon’s singing, a processed patchwork of falsetto that is front and center in an album that seems more interested in cohesion and atmospherics than in any one definitive tone.

“Hey Ma” is a dreamy synth number that finds Vernon reminding us, or perhaps himself, that it’s “Tall time to call your Ma” — the song’s simplicity is a welcome reprieve from the darkness that pervaded some of the group’s past efforts. Overall, bliss outweighs despondence this time around. “iMi” finds Vernon celebrating the comfort of familiarity, while the piano-driven “Naeem” features more abstract observations that are still positive, evoking some of Feist’s brooding ballads.

Even if “i,i” finds Vernon embracing a new form of vulnerability, he’s not going there alone. As usual, this album has a host of guest turns. The album’s cast includes the National’s Aaron and Bryce Dessner, James Blake, Moses Sumney, and Vernon’s unlikely influence, ‘80s pop piano man Bruce Hornsby. In total, over 30 musicians were involved, though Hornsby’s (brief) contribution to the astutely arranged “U (Man Like)” is the best of the bunch.

Some will no doubt ponder why it takes a village to make a record that feels far more isolated than communal, but the overall effect of “i,i” is not that of a disaffected wall of sound. Neither is it meant to be Vernon’s “happy” record, though such reductive distinctions are rarely an accurate portrayal of an album’s true intent. Instead, it’s wild and fragmented, as nature intended.