Like all the best science writing, Dunbar's book combines original research with an ability to think laterally and make connections with other disciplines.
His key finding is that there is a correlation between the size of the neocortex in primate species and the size of their social groups. In humans the figure for the latter is about 150 - that is, the number of people we feel we "know". (In our mixed-up modern world we can feel we "know" someone without having met them - hence the Princess Diana phenomenon.) Professor Dunbar disentangles the implications with entertaining lucidity.
As anthropologists have long pointed out, power and status are vital assets for males in the mating game. Adolf Hitler had many women admirers - and it certainly wasn't for his sense of humour, his trustworthiness or his personal warmth. Of the three women closest to him, two committed suicide and the third either committed suicide or was killed by him. The last, Geli Raubal, is the focus of Ronald Hayman's Hitler and Geli (Bloomsbury pound;7.99), an absorbing enquiry into the murky world of Hitler's personal life. And very murky it was. Geli was not only his mistress but his half-niece. Incest and sado-masochism, it seemed, ran in the family. Hayman's historical detective work casts important new light on the man who could make anyone believe in evil.
The brief, unhappy life of the writer Isabelle Eberhardt, chronicled in Annette Kobak's Isabelle (Virago pound;7.99), reads with historical hindsight like a case study in fin de si cle decadence. The obsession with death; the drug-taking and sexual ambivalence; the oriental exoticism - all mirrored the concerns of other writers and artists of the time. Annette Kobak's book could have made more of this wider cultural context, but as an intimate portrait it makes for absorb-ing reading.
No figure, perhaps, encapsulated the iconoclastic, free-thinking spirit of modern science more than the subject of John and Mary Gribbin's Richard Feynman: a life in science (Penguin pound;7.99). As well as recounting the legend of the "playboy physicist", the authors explain Feynman's original contributions to quantum mechanics and show, above all, how he was driven by an ability to take nothing for granted, an ability that led him to uncrack everything from the Challenger disaster to the workings of Mayan astronomy.
A word, finally, for Samuel Charteris's The Legacy of the Blues: the Art and Lives of 12 Great Bluesmen (Marion Boyars pound;10.95). First published 20 years ago, this brief but evocative study, which includes transcriptions of lyrics and some excellent photographs, is written with a novelist's eye and a poet's feel for the rhythms of the music.