A Universe of Consciousness: How Matter Becomes Imagination is the title of a 2000 book by biologists Gerald Maurice Edelman and Giulio Tononi; published in UK as Consciousness: How Matter Becomes Imagination. This book, written with Giulio Tononi, is the culmination of a series of works by Gerald Edelman on the workings of the brain which include Neural Darwinism and Bright Air, Brilliant Fire. Precis It is divided into six sections: the first three cover existing work from philosophical, neurological and Darwinian perspectives. Part IV presents the novel thesis of the work: the Dynamic Core Hypothesis. The remaining two parts explore how it resolves various philosophical and practical issues. The Background Since Descartes, philosophers have been occupied with the concept of consciousness and its subjective nature has posed a special problem for science. Its nature arises from the neuronal structures in the brain and some understanding of these, together with the experimental tools needed to explore them, is given in the following chapters. They then recapitulate Edelman's still controversial theory of somatic selectionism during early development which controls the topology of a particular brain and enables restructuring in response to experience. They argue that memory is not a symbolic representation but a reflection of how the brain has changed its dynamics in order to achieve motor activity. This leads to a discussion of primary consciousness which integrates with perception into a means of directing immediate behavior and requires significant levels of reentrancy to achieve its effects. The Dynamic Core Hypothesis The problem of integrating, or binding, the activity of functionally segregated areas of the brain in order to concentrate attention on a particular activity in a short amount of time (typically 100-250 msecs) after the presentation of a stimulus is explored by means of large-scale simulations. It is shown that this can only happen if some elements interact more strongly among themselves than with the rest of the system including a large amount of reentrancy. These functional clusters are only slowly coming into the range of PET or fMRI scanning technology which commonly require much longer time scales. At any given time, only a small subset of the neuronal groups in the brain are contributing directly to consciousness and this cluster is called a dynamic core. It represents a single point of view and each different state of consciousness corresponds to a different subset. Some dissociative disorders such as schizophrenia