The measurement of time dependent fluctuations of observables (quantum noise measurements) an increasingly important part of transport experiments. They allow access to information about hitherto unavailable from steady state measurements alone. We will illustrate the basic theoretical concepts, and illustrate how they can be used to extract information about the spectral, dissipative, and entanglement properties of non-equilibrium quantum dots. cond-mat/0602063, cond-mat/0310578"