"At Work in the Field of Birth" is an ethnographic study of midwifery in Canada in the wake of its historic transition from the margins as a grassroots social movement devoted to low-tech, woman-centered care to a regulated profession within the public health care system. In January 1994, after decades of lobbying by midwives and their supporters, the province of Ontario recognized midwifery as a profession for the first time in more than a century. Through stories about becoming and being a midwife and stories about receiving midwifery care, this book describes how fundamental tenets of midwifery philosophy and practice--the meaning of tradition, natural birth, and home birth, and the place of medical technology in midwifery--are being reworked by the practical and ideological challenges of midwifery's new place within the formal health care system. MacDonald presents contemporary midwifery as a complex cultural system in which "nature" and "tradition" emerge as dynamic rather than esssentialized social categories of meaning and experience.