Super- and subradiance have been an active topic of research since the seminal paper of Dicke on collective emission of atoms confined within a distance that is small compared to the wavelength of the resonantly emitted radiation. The behaviour of the single and multiple-excitation states of interacting atoms can be understood in terms of the collective eigenstates of an effective non-Hermitian Hamiltonian, which exhibit enhanced (superradiant) and suppressed (subradiant) decay rates, together with level shifts (collective Lamb shift). Also, recent experiments have demonstrated both subradiance and superradiance in large, dilute atomic clouds. We will present the way such an atomic cloud decays to the ground state with two methods, the Density Matrix solution and the Quantum Stochastic Wavefunction method. We will also present how to find the most probable decay “path” and how to calculate the probability of each probable decay path.