Since it is obligatory upon us to start seeking knowledge (1), reading islamic books is highly fundamental. There is no stopping point to seeking knowledge; we buy books and benefit from them for as long as we live.
This article will explain the reasoning of the high importance of these books and recommended books to read.
It is our duty as a Muslim to be pious and knowledgeable. As knowledge is taken away by the passing of the scholars, we need to gather as much knowledge as we can, as there will be time in which people might start asking you for knowledge.
Abdullah ibn Amr reported that the Prophet ﷺ said:
“Verily, Allah does not withhold knowledge by snatching it away from his servants, but rather he withholds knowledge by taking the souls of scholars, until no scholar remains and people follow ignorant leaders. They are asked and they issue judgments without knowledge. Thus, they are astray and lead others astray.” (2)
This is one of the reasons we need to gain as much knowledge as we can; we don't want to be without knowledge at a time where there is only ignorant leaders left to take knowledge from.
A good starting point would be to start off with simple and concise books, as knowledge is only to be sought gradually. Books like The Conditions of La Ilaha Illa Allah, Tawheed and Aqeedah books are one of the great starting points.
Sheikh Salih al-Fawzan (hafidhahullah) said:
"Seeking knowledge begins by learning fundamentals gradually from concise books in each discipline which are memorised and understood from the scholars. So one does not read and begin with detailed books, nor books that mention differences of opinion and various statements [of scholars]. Indeed knowledge is only sought gradually." (3)
As always, I hope insha-allah you have benefitted from this. May Allah bless you, and shukran.
1. Anas ibn Malik reported that the Prophet ﷺ said: "Seeking knowledge is obilgatory upon every Muslim." Sunan ibn Majah 224, graded Sahih according to Al-Albani
2. Sahih al-Bukhari, Sahih Muslim 2673, graded Muttaqun Alayhi (agreed upon.) according to Al-Bukhari and Muslim.