You can access your entire library. You can delete at will. The music not on your device will have a cloud with a download arrow next to it. So if you need room just delete what you don't want and download what you do want. Since you can download at will and once you start playing a playlist the rest of the playlist will download automatically it is nearly like streaming, except that the file stays there until you delete it. I played an album not on my device, that downloaded while listening, that way yesterday.