Mesoscopic physics considers systems of appropriate size and at time scales of the order of decoherence time, which allows us to analyse the transformation of information from a quantum state to a classical signal, occurring in a process of quantum measurement. We concentrate on the limiting cases of weak and strong coupling between a mesoscopic source of noise and a subsystem functioning as a detector. In the ``weak coupling'' part we elaborate on the idea of cross-correlation measurements for quantum noise detection and develop a set of original methods to tackle the perturbation theory up to fourth order. In the ``strong coupling'' part we provide an exact solution for one-dimensional system out of equilibrium, strongly interacting with a localized state and predict some remarkable experimentally verifiable features, such as Fermi-edge singularity in the noise induced transition rates and unusually pronounced manifestation of non-Gaussian noise effects.