3) Bandcamp has a surprising amount of music from around the world and you can almost always listen to everything before you buy. When I find music via bandcamp it is usually via small labels I found via someone I found out about elsewhere (small labels are not usually the "sign your life away" type so one artist is frequently on a bunch of small labels that have similar music). The website is not that great, look for label links in the upper left of the page (and when you go to a particular album it will often go to the artist's page outside the label and you can find their music on other labels from there). In addition to the Bandcamp Weekly that someone else mentioned they have a bunch of lists with short (meh quality) articles and a bunch of music that you can listen to right there. Note: beware of excessive PayPal currency conversion fees if you buy something in a different currency, either use a credit card if those fees are reasonable or transfer money to PayPal and convert to different currencies on the wallet page and use those pre-converted funds.
Electronic and Experimental Music: Technology, Music, and Culture by Thom Holmes.
I'll add a few other resources:
1) Soundcloud (the free version) is the best way I have found to find new music: https://soundcloud.com/
2) NPR's All Songs Considered and Tiny Desk Concerts are also excellent:
https://www.npr.org/sections/allsongs/
https://www.npr.org/series/tiny-desk-concerts/
https://www.npr.org/series/761983313/tiny-desk-playlists
3) Bandcamp has a surprising amount of music from around the world and you can almost always listen to everything before you buy. When I find music via bandcamp it is usually via small labels I found via someone I found out about elsewhere (small labels are not usually the "sign your life away" type so one artist is frequently on a bunch of small labels that have similar music). The website is not that great, look for label links in the upper left of the page (and when you go to a particular album it will often go to the artist's page outside the label and you can find their music on other labels from there). In addition to the Bandcamp Weekly that someone else mentioned they have a bunch of lists with short (meh quality) articles and a bunch of music that you can listen to right there. Note: beware of excessive PayPal currency conversion fees if you buy something in a different currency, either use a credit card if those fees are reasonable or transfer money to PayPal and convert to different currencies on the wallet page and use those pre-converted funds.
https://daily.bandcamp.com/lists/electronic-folklore-list
https://ostinatorecords.bandcamp.com/
https://zzkrecords.bandcamp.com/
https://wonderwheelrecordings.bandcamp.com/
https://palenquerecords.bandcamp.com/
https://galletascalientesrecords.bandcamp.com/
https://analogafrica.bandcamp.com/
https://sahelsounds.bandcamp.com/
https://theoutlawocean.bandcamp.com/
Also, the history of music can be broken down into the history of instruments and of the movement of people.