In the UK, and most places, Revolver was released after Rubber Soul.
In the US, Revolver was released after "Yesterday and Today", a collection of 45's and other songs from the UK Rubber Soul.
The US Revolver was interesting because Paul did most of the lead vocals. It also confirmed that George Martin is one of the great pop music producers of the last 50 years! You can see Martin's creative influence all over this album.
George had 3 songs, including the classic "Taxman".
John was limited to lead vocals on two songs, like "Tomorrow never knows" and "She said, she said". He had more tracks on the UK version. He had a couple more in the UK Revolver and were released in the aforementioned "Yesterday and Today:.
Why were the US and UK versions different? I don't know but they were.
What else do they say about Revolver:
"If you don't like Revolver, then you probably don't like rock music." (Reviews)