This issue of Interventional Cardiology Clinics, edited by the series Editor-in-Chief, Dr. Matthew Price, will cover Transcatheter Closure of Patent Foramen Ovale. Some of the topics discussed in this issue include, but are not limited to, PFO and the Interatrial Septum: Clinical-Anatomic Correlations, Current Dataset for PFO Closure in Cryptogenic, Stroke: Randomized Clinical Trials and Observational Studies, PFO closure: Devices and Technique, Identification and quantification of PFO-mediated shunts: echocardiography and transcranial Doppler, PFO closure for Hypoxemia, and Imaging Assessment of the interatrial Septum for ASD and PFO closure, among others.