Spirits Having Flown is regarded today as something of a letdown, representing the tail-end of the Bee Gees' period of greatest success, perhaps because it preceded a two-year layoff that, in turn, heralded a decline in their fortunes.

At the time, however, no one heard anything less than what they expected -- beautiful slow dance numbers ("Too Much Heaven," "Love You Inside Out"), achingly gorgeous romantic numbers ("Reaching Out"), soaring ballads ("Spirits (Having Flown)"), and pounding dance-rock numbers ("Tragedy").

If a few songs on the LP's second side, like "Stop (Think Again)" or "Search, Find," weren't quite up to that high standard, even the latter song displayed dazzling interwoven vocals on the choruses (which were pretty infectious) that made the trip worthwhile.

The record showcased the usual superb singing, and featured the most delicate and ambitious production and arrangements in their history.

It may have lacked the spirit of freedom and experimentation found on Main Course or Children of the World, but in its place was a boldness that manifested itself not only in the singing, but also the most intricate and ambitious production and arrangements of the group's entire history.

This was also the first Bee Gees album to get serious airplay on black radio stations, a major breakthrough for the trio and one of the last bits of unfinished business in the group's move into soul music, which also likely helped -- along with three chart-topping singles, the major tour that followed, and the network television special in the wake of the tour -- in propelling Spirits Having Flown to 35 million sales.