Len Fisher's second book (his first, How to Dunk a Doughnut, was published in 2002) looks at the business of finding, developing and (sometimes) establishing scientific ideas, be they good, bad or downright dotty. He does this by looking at some of the less examined ramifications of great scientific questions, giving rise to much thought and amusement during the process.

The book's title is explained in the opening chapter, which briefly recounts the debate about the existence of the human soul and then the various efforts to prove its existence, from da Vinci's use of surgery to more recent bids to weigh it. Fisher's engagingly discursive style then takes the reader onto the issue of mass, why this differs from weight, and how the elusive particle, the Higgs boson, is usually held to be responsible for this curious quantity.

Next is Galileo's turn, proceeding from his physical specifications for hell, to one or two little-known applications of his work on falling bodies and his heretical support for the Copernican model of the Solar System. Sir Isaac Newton, Robert Boyle and Luigi Galvani and his experiments with electricity on the legs of unfortunate frogs, all come in for similar treatment.

The grand finale is a discussion of life itself, pitching the 'mechanists' against the 'vitalists', and a short chapter and appendix on the "Necessary Mysteries".

These last, which he calls "anticommon sense", are the author's gentle introduction to some essential scientific beliefs that "lie alongside the other set of eternal mysteries that are the province of philosophy and religion". Some of these he then works through, on an elementary level: waves, atoms and molecules, gravity and other forces.

This slim book runs to just 147 pages of text, with a further 57 pages of useful notes and amplifications.

This is the sort of book that leaves most readers wanting more.

---