It’s a huge task to classify 400000
books. However, according to the custom,
all books can be categorized into 10 categories:
000 for general, 100 for philosophy, 200
for religion, 300 for natural science, 400
for applied science, 500 for social science,
600 for Chinese history and geography, 700
for world history and geography, 800 for
language and lecture, and 900 for arts.
After understanding the 10 categories,
we should be interested in reading and cherish
the books more.