I had a dream where weird linguistics books rained in Japan

I was for whatever reason walking around somewhere in Japan and linguistics books about conlanging (language creation), started raining down from the sky.

Everyone was rushing to grab one in the dream. The books were very thick and had a colorful cover, similar to the picture but with colors other than red.

I've never been to Japan, nor have I read any linguistics book or studied linguistics. I have tried conlanging once though.