What is the difference between "a user" and "current user" API's

[#1]

I want to use the Spotify API's and am in the process of deciding which ones i want to use for my Website but I can't figure out the difference between "a user" and "current user"

[Peter_Schorn]

The current user is the one that you authorized with using either the authorization code flow or authorization code flow with proof key for key exchange. See the authorization guide.