These new books only sometimes live up to their series title, Big Science Ideas. Although each volume introduces a science concept related to animals, it often acts as a loose umbrella topic rather than a truly unifying theme. The majority of each book's space is devoted, instead, to individual examples that are briefly covered in one or two spreads. Symbiosis is the strongest of the bunch, as it frequently refers back to the different kinds of symbiosis introduced in the first spread: mutualism, commensalism, parasitism, and predation. Despite a frequent lack of cohesion, the books do offer an overview of generally interesting, useful topics. One special highlight is the many striking photos on the covers and throughout each book.