bit about hydrogen and helium but my excuse is that they make up the bulk of the visible matter in the Universe. Similarly wavelengths, which, like frequency, can be used to describe the behaviour of different kinds of solar energy from X-rays to radio waves. You do not have to be a geek to appreciate such matters, witness a useful mnemonic for the relationship between wavelength and frequency to be found in one of the tales of diplomatic life by Lawrence Durrell: " If there is anything worse than a soprano, " said Antrobus judicially, as we walked down the Mall towards his club, " it is a mezzo-soprano. One shriek lower in the scale, perhaps, b ut with higher candle-po wer . " Just bear in mind that he got it the wrong way round. There are many paradoxes in my account. The Sun drives the weather and keeps the Earth's temperature at tolerable levels, it is the basis of photosynthesis and thus the life of plants and the creatures they sustain, and its magnetic field shelters us from dangerous cosmic rays; yet at the same time the ultraviolet (UV) part of the solar spectrum may damage DNA and human tissue, solar flares can destroy spacecraft, power systems and computers, and there is every indication that the Sun precipitated a mini Ice Age less than two centuries ago. Sunshine allows us to generate vitamin D but too much of it can lead to skin cancer and cataracts. Etcetera etcetera.

The Sun is an account of the many ways in which our nearest star affects our planet, how its influence has changed over the last few centuries and millennia, and the extent to which we can predict its future impact. The Sun's rays foster the formation of Vitamin D by our bodies, but it can also promote skin cancer, cataracts, and mutations in our DNA. Besides providing the warmth and light essential to most animal and plant life, solar energy contributes substantially to global warming. Although the charged particles of the solar wind shield us from harmful cosmic rays, solar storms may damage artificial satellites and cripple communication systems and computer networks. The Sun is the ideal renewable energy source, but its exploitation is still bedevilled by the problems of storage and distribution. Our nearest star, in short, is a complex machine which needs to be treated with caution, and this book will equip every reader with the knowledge that is required to understand the benefits and dangers it can bring.