The medical and nursing care systems discussed in Chaps. 3, 4, 5, 6, 7, 8, and 9, along with the public health measures introduced by the government in Chaps. 10, 11, 12, 13, 14, and 15, work together to support the health of the Japanese people. Health centers play a central role in these community health activities. Health policies cannot succeed merely by the national government enacting laws and providing financial assistance to prefectures and municipalities; daily public health activities by public health doctors, PHNs, and other staff at prefectural and municipal governments are essential. It is fundamental and critical for PHNs at municipalities and health centers to visit households, assess the health status of each household, understand the health condition of the area, and provide guidance to prevent illness (health guidance). Once people contract a disease, they will visit a clinic or hospital using public health insurance (Chap. 7). If they encounter problems related to social issues, they are supported by health centers and municipalities, allowing them to receive appropriate medical care, administrative assistance, and nursing care (Chap. 8).