This book includes two topics. Part 1 is on atom-photon interactions without the rotating-wave approximation (RWA), including the Lamb shift, the quantum Zeno and anti-Zeno effect, the polarizability, the superradiance and the subradiance. We go beyond the RWA with a unitary transformation. After the transformation, the Hamiltonian only has rotating-wave terms. The effects of the counter rotating terms include a level shift and a modification factor of the rotating-wave terms. Part 2 is on the reflection and the transmission in a standing wave coupled electromagnetically induced transparency...