Book excerpt: Accurate information about body structure and posture is fundamental for effective control of our actions. It is often assumed that healthy adults have accurate representations of their body. Although people's abilities to visually recognize their own body size and shape are relatively good, the implicit spatial representation of their body is extremely distorted when measured in proprioceptive localization tasks. The aim of this thesis is to understand the nature of spatial distortions of the body model measured in those localization tasks. We especially investigate the perceptual-cognitive components contributing to distortions of implicit representation of the human hand and compare those distortions with the one found on objects in similar tasks.