C. T. Russell Originally published in the journal Space Science Reviews, Volume 136, Nos 1 4. DOI: 10. 1007/s11214-008-9344-1 (c) Springer Science+Business Media B. V. 2008 The Sun-Earth Connection is now an accepted fact. It has a signi cant impact on our daily lives, and its underpinnings are being pursued vigorously with missions such as the Solar TErrestrial RElations Observatory, commonly known as STEREO. This was not always so. It was not until the middle of the nineteenth century that Edward Sabine connected the 11-year geomagnetic cycle with Heinrich Schwabe s deduction of a like...