Whereas ''An Inconvenient Truth'' framed the crisis that climate negotiations are tackling, this followup spells out what needs to be done. Based on 30 of Gore's 'Solutions Summits' as well as one-on-one discussions with leading experts across multiple disciplines, the book aims, in Gore's words, "to gather in one place all of the most effective solutions that are available now". Gore naturally focuses on energy, the source of most anthropogenic greenhouse gas emissions, and discusses many underappreciated strategies such as concentrated solar thermal power and cogeneration. He also devotes a full chapter to soil, a major carbon sink that is gradually degrading. Farming strategies for restoring soil carbon are described, including biochar, a porous charcoal that can potentially enhance the soil sink while providing a source of low-carbon power.... ''Our Choice'' is replete with lush photos and simple but powerful charts. This a must-read book for those who want a primer on all the key solutions countries will be considering at Copenhagen.〔Romm, Joseph. ("Our Choice: A Plan to Solve the Climate Crisis", ) ''Nature Reports Climate Change'', online: October 2, 2009〕