The ISEE-1 and ISEE-2 spacecraft, separated by a few hundred kilometers, provided data on the magnetic field profiles across the magnetopause during four passes. The magnetosheath field was northward in one pass, slightly southward in another, and strongly southward in two. The magnetopause velocity varied widely, from 4 to over 40 km/s, and changed rapidly. The magnetopause thickness ranged from 500 to over 1000 km. Reconnection was evident when the magnetosheath field was southward, but not as classic rotational discontinuity signatures. Instead, it was observed as flux transfer events (FTEs), where reconnection starts and stops in minutes, causing flux tubes to be ripped from the magnetosphere. FTEs were detected in both the magnetosheath and outer magnetosphere, altering the boundary normal. These events invalidate traditional 2D analyses of the magnetopause. FTEs likely dominate reconnection at the magnetopause and may cause magnetopause oscillations and outer magnetosphere pulsations. Estimated FTE flux transfer rates were about 2×10¹² Maxwells per second. Other events not detected by ISEE could have led to higher reconnection rates. The magnetopause has been studied for over a decade, revealing its average position and shape, which varies with geomagnetic activity. The magnetopause moves at speeds greater than spacecraft, with periodic velocities leading to multiple crossings. The boundary's magnetic signature is complex, with many different features. Comparing these with theory is difficult due to complexity, unknown relative velocity, and boundary orientation changes. The ISEE mission aims to understand the magnetopause structure through high-resolution magnetic and electric field measurements, low-energy plasma, and energetic particles. Many measurements are three-dimensional, allowing accurate flow and anisotropy analysis. Duplicate measurements on closely spaced spacecraft enable time-of-flight analysis to determine boundary velocities and thickness. Recent studies suggest reconnection occurs at polar cusps (impulsive) and quasi-steady state reconnection. This paper examines four magnetopause crossings, showing reconnection occurs when the magnetosheath field is southward, consistent with Haerendel et al. (1978). However, the exact location of reconnection initiation remains unclear due to limited data.The ISEE-1 and ISEE-2 spacecraft, separated by a few hundred kilometers, provided data on the magnetic field profiles across the magnetopause during four passes. The magnetosheath field was northward in one pass, slightly southward in another, and strongly southward in two. The magnetopause velocity varied widely, from 4 to over 40 km/s, and changed rapidly. The magnetopause thickness ranged from 500 to over 1000 km. Reconnection was evident when the magnetosheath field was southward, but not as classic rotational discontinuity signatures. Instead, it was observed as flux transfer events (FTEs), where reconnection starts and stops in minutes, causing flux tubes to be ripped from the magnetosphere. FTEs were detected in both the magnetosheath and outer magnetosphere, altering the boundary normal. These events invalidate traditional 2D analyses of the magnetopause. FTEs likely dominate reconnection at the magnetopause and may cause magnetopause oscillations and outer magnetosphere pulsations. Estimated FTE flux transfer rates were about 2×10¹² Maxwells per second. Other events not detected by ISEE could have led to higher reconnection rates. The magnetopause has been studied for over a decade, revealing its average position and shape, which varies with geomagnetic activity. The magnetopause moves at speeds greater than spacecraft, with periodic velocities leading to multiple crossings. The boundary's magnetic signature is complex, with many different features. Comparing these with theory is difficult due to complexity, unknown relative velocity, and boundary orientation changes. The ISEE mission aims to understand the magnetopause structure through high-resolution magnetic and electric field measurements, low-energy plasma, and energetic particles. Many measurements are three-dimensional, allowing accurate flow and anisotropy analysis. Duplicate measurements on closely spaced spacecraft enable time-of-flight analysis to determine boundary velocities and thickness. Recent studies suggest reconnection occurs at polar cusps (impulsive) and quasi-steady state reconnection. This paper examines four magnetopause crossings, showing reconnection occurs when the magnetosheath field is southward, consistent with Haerendel et al. (1978). However, the exact location of reconnection initiation remains unclear due to limited data.