This book reflects the state of the art of our understanding of the WNT signaling system, which comprises a network of signaling pathways initiated by the secreted WNT lipoglycoproteins, which are crucial for embryonal development, stem cell regulation, tissue homeostasis and repair. Dysfunction of this evolutionarily conserved signaling system leads to many diseases including developmental disorders, diverse forms of cancer, fibrosis, neurodegenerative disease and many more. The WNT signaling system is built upon 19 mammalian, secreted WNT lipoglycoproteins that interact with a plethora of...