Science Fiction about overpopulation of the human race and 'converging'. Published before 1997.

[Kat]

Hubby remembers reading a book when he was in high-school - so the book was published pre-1997.
What he remembers about the book is that the world population has reached 20billion(?), and converged or evolved - he says the whole consciousness of the human race becomes one, like maybe a hive mind or something to that effect. He doesn't recall aliens or magic. Although now he says there 'might have been aliens guiding humans'.
It's a long shot, and I will continue to search elsewhere but if this rings any bells for anyone else then let me know :)
Thanks!

[beichst]

Perhaps Childhood's End? It is definitely older tnan 1997 (from 1953) and does have aliens guiding humans. Too, it does have a combined consciousness that arises:

"As Rashaverak explains, the time of humanity as a race composed of single individuals with a concrete identity is coming to an end. The children's minds reach into each other and merge into a single vast group consciousness. "