As seismic waves travel through the earth, the visco-elasticity of the earth's medium will cause energy dissipation and waveform distortion. This phenomenon is referred to as seismic absorption or attenuation. In hydrocarbon reservoir description, seismic absorption can be used as an attribute to interpret for fluid units. In seismic data processing, this information can be used to enhance seismic data resolution by means of absorption compensation. The absorptive property is described by a quality factor, Q, which defines the energy decay and a velocity dispersion relationship. The quality factor and the velocity govern the propagation of seismic energy in the earth. The content of this book covers four new ideas to deal with the estimation and application of seismic absorption. These ideals are: to estimate the quality factors in CMP gathers using peak frequency variation; to stabilize attenuation compensation using a least square inverse scheme; to estimate a quality section using an AVO-like analysis method and to treat the multi-dimensional attenuation compensation as a de-blurring process.