I'm reading Paul Davies 'The Eerie Silence' at the moment.
Davies is a physicist with an ongoing interest in the Big Questions such as the one he addresses in this book: If we are not alone in the universe, where is everyone?
It's a slightly depressing read for someone such as myself who does hold the hope that we are not the only creatures in the cosmos. Davies (unfortunately for optimism) argues fairly persuasively that if intelligent life is pervasive, we should probably already be aware of it - if we're looking in the right places, that is. One of the intriguing things about this book is that Professor Davies, who in 2005 took up the chair of the SETI Post-Detection and Technology Taskgroup, outlines some good reasons why alien intelligence might very well deserve the adjective 'alien'. If other beings exist out there, he reasons, anticipating what they might be like according to our own preconceptions is probably the wrong way to go about finding evidence of them.
Nevertheless, this very level-headed view of ET hunting does serve to strengthen one of the key ideas behind Watching Europa: that discovering signs of extraterrestrial life, even if it is non-intelligent, would be a remarkable and awe-inspiring event.