The study of the Earth's magnetic field is one of the oldest scientific disciplines. Research in geomagnetism enabled information to be deduced about the Earth's interior, the electrodynamics of the upper atmosphere at altitudes above 100 km, and the processes at work in interplanetary space and even on the surface of the Sun.
Regular recordings of the geomagnetic field elements were commenced on a global scale in 1841, initially with hourly recordings, but 5 years later, continuous recordings were introduced. One of the oldest of these continuous recording stations is the Colaba-Alibag magnetic observatory in India. The Earth's Magnetic Field was commissioned to commemorate 150 years (1841–1991) of continuous, uninterrupted observations of the Earth's magnetic field by that observatory. Therefore, it is inevitable that the book emphasizes much of the Indian contributions to studies in geomagnetism. Two of the eight chapters are devoted to this aspect: Chapter 5 on the historical aspects of geomagnetism in India and chapter 7 on the Indian contributions to modern geomagnetism.