Greetings KAding,
It is from the minor signs of the last hour that knowledge will be taken away from us. See these ahadeeth:
Anas ibn Malik said, "I shall tell you a hadith which I heard from the Messenger of Allah, and which no-one will tell you after me. I heard him say, 'Among the signs of the Hour will be the disappearance of knowledge and the appearance of ignorance. Adultery will be prevalent and the drinking of wine will be common. The number of men will decrease and the number of women will increase until there will be fifty women to be looked after by one man.' " This hadith was reported in the two Sahihs from the hadith of 'Abd Rabbihi.
'Abdullah said, "The Prophet said, 'Just before the Hour, there will be days in which knowledge will disappear and ignorance will appear, and there will be much killing.' " [Ibn Majah; also narrated by al-Bukhari and Muslim, from the hadith of al-A'mash]
How will this knowledge be taken from us? Through the death of our learned scholars. See this hadeeth:
'Abdullah b. 'Amr b. al-'As reported Allah's Messenger (may peace be upon him) as saying: Verily, Allah does not take away knowledge by snatching it from the people but He takes away knowledge by taking away the scholars, so that when He leaves no learned person, people turn to ignorant as their leaders; then they are asked to deliver religious verdicts and they deliver them without knowledge, they go astray, and lead others astray. (Sahih Muslim)