Readers of this ebook are doubtless aware of vaccination activities in their institutions or communities, and many are involved in the organization or support of such activities. Nonetheless, it is likely that few are aware of the organizational complexity of the global vaccine enterprise, which includes public health authorities at every level — global, national, regional, and local; national and supra-national regulatory authorities; national vaccine recommending bodies; professional medical societies (and their associated recommending bodies); vaccine manufacturers; non-governmental organizations (NGOs); research institutions; academic researchers; and other similar entities. The 8 papers included in this ebook can only provide a glimpse of the roles and activities involved in the global vaccination enterprise, but it is our hope that they will enrich the readership's understanding of this topic and prove useful to the readership in their professional activities.