The paper by C. T. Russell and R. C. Elphic examines the magnetic field profiles across the magnetopause obtained by the ISEE-1 and -2 spacecraft during four passes. The magnetosheath field was observed to be northward in one pass, slightly southward in another, and strongly southward in two others. The velocity of the magnetopause varied widely, from 4 to over 40 km/s, and the thickness ranged from 500 to over 1000 km. Evidence for reconnection was found when the magnetosheath field was southward, primarily in the form of flux transfer events (FTEs) rather than classic rotational discontinuity signatures. These FTEs result in the rapid ripping off of flux tubes from the magnetosphere and can be detected in both the magnetosheath and the outer magnetosphere. The presence of FTEs invalidates traditional 2-dimensional analysis of magnetopause structure and suggests that they may be the dominant means of reconnection on the magnetopause, contributing to magnetopause oscillations and pulsations in the outer magnetosphere. The flux transfer rate estimated by ISEE was around \(2 \times 10^{12}\) Maxwells per second, and the authors suggest that undetected FTEs could have led to even higher reconnection rates. The paper also reviews the historical study of the magnetopause, including its position, shape, and variability, and discusses recent findings on reconnection at the magnetopause.The paper by C. T. Russell and R. C. Elphic examines the magnetic field profiles across the magnetopause obtained by the ISEE-1 and -2 spacecraft during four passes. The magnetosheath field was observed to be northward in one pass, slightly southward in another, and strongly southward in two others. The velocity of the magnetopause varied widely, from 4 to over 40 km/s, and the thickness ranged from 500 to over 1000 km. Evidence for reconnection was found when the magnetosheath field was southward, primarily in the form of flux transfer events (FTEs) rather than classic rotational discontinuity signatures. These FTEs result in the rapid ripping off of flux tubes from the magnetosphere and can be detected in both the magnetosheath and the outer magnetosphere. The presence of FTEs invalidates traditional 2-dimensional analysis of magnetopause structure and suggests that they may be the dominant means of reconnection on the magnetopause, contributing to magnetopause oscillations and pulsations in the outer magnetosphere. The flux transfer rate estimated by ISEE was around \(2 \times 10^{12}\) Maxwells per second, and the authors suggest that undetected FTEs could have led to even higher reconnection rates. The paper also reviews the historical study of the magnetopause, including its position, shape, and variability, and discusses recent findings on reconnection at the magnetopause.