This Ebook aims to review basic understandings and give current opinions about several important aspects of glycosylphosphatidylinositol-anchored (GPI) protein biology from leading experts in this exciting and emerging field. The scope ranges from micro-domain localization and signaling to proteomics aspects, biophysical behavior through trans-cellular mobility to chemical synthesis of GPI mimics and finally modification of multi-scaled membrane surfaces and potential medical and biotech uses. The applied slant makes it very useful to the current state of knowledge. It is hoped that it will prove to be of considerable interest to students and researchers in this field.