In this issue of PET Clinics, guest editors Drs. Harshad Kulkarni and Abass Alavi bring their considerable expertise to the topic of Theranostics. Tops experts cover key topics such as total-body PET in theranostics: transforming treatment planning and follow-up; FAP-targeted imaging and therapy; theranostics in neuroendocrine neoplasms: integrating imaging, therapy, and dosimetry; theranostics: when targeting imaging leads to a targeted therapy; and much more.