The Browser allows you to browse the metadata cache and add tracks to your playlist. It includes a powerful interactive mode.
The Browser is defined in emms-browser.el and is included in the emms-all setup level. For more information about Emms setup levels see See Simple Setup.
You can also manually add the Browser to your Emms setup by loading it explicitly with:
To be properly useful, you should do M-x emms-add-directory-tree to all the files you own at least once so that the cache is fully populated.