Encyclopedia Brown was one of the first mystery series I remember reading, getting the books (if I remember correctly so many decades later) from Scholastic, ordered via the elementary school I went to. I guess it started something, because I'm clearly still a big mystery addict.
And right now,
Encyclopedia Brown, Boy Detective, by Donald J Sobol, which is the first in the series, is on sale in the US for $1.99.
Kindle US:
https://www.amazon.com/dp/B000UZQI60
Kobo US:
https://www.kobo.com/us/en/ebook/enc...oy-detective-1