Perry: The Babylonians led by Nebuchadnezzar defeated the Egyptians but did not conquer Egypt. The refererence quoted by Wikipedia is from the book "Nebuchadnezzar and Babylon" (Wiseman, 1983). I did not get that book, but I would like to read in it what is the proof for that assertion. As far as I know there is no such a proof. Nebuchadnezzar, as a king, fought against two egyptian kings, namely, Hophra (589 - 570 BCE) and Amasis II (570-526 BCE). Before Nebuchadnezzar destroyed Jerusalem in 587 BCE, Hophra went against him to help the king of Judah, Zedekiah. Hophra and his army were defeated by Nebuchadnezzar but not conquered by him, because Hophra could went back to Egypt as Jeremiah said:
5 Pharaoh’s army had marched out of Egypt, and when the Babylonians who were besieging Jerusalem heard the report about them, they withdrew from Jerusalem. 6 Then the word of the Lord came to Jeremiah the prophet: 7 “This is what the Lord , the God of Israel, says: Tell the king of Judah, who sent you to inquire of me, ‘Pharaoh’s army, which has marched out to support you, will go back to its own land, to Egypt. 8 Then the Babylonians will return and attack this city; they will capture it and burn it down.’ (Jeremiah 37:5-8)
Then, Amasis II overthrew Hophra and became king of Egypt, so Hophra had to flee to other country. Then Hophra got the help of Babylon to recover his reign but he was killed by Amasis' army in 567 BCE. Also, there is a babylonian tablet (BM33041) of the 37th year of Nebuchadnezzar, which seems to be 568 BCE, where it is narrated the battle between Amasis and Nebuchadnezzar. Nevertheless, due to the damage of some portions of the tablet we can't know for sure the result. At worse, Amasis lost the battle and went back to Egypt, but Nebuchadnezzar could not conquer the land of Egypt, because Amasis continued reigning until 526 BCE, whereas Nebuchadnezzar died in 562 BCE, six years after that battle. So, the land of Egypt was not desolated by Nebuchadnezzar, nor the 40 years could be fulfilled during Nebuchadnezzar reign.