Introduction /Patrick McNamara, Charles L. Nunn, andRobert A. Barton --Ecological constraints on mammalian sleep architecture /Isabella Capellini ... [et al.] --Sleep in insects /Kristyna M. Hartse --Schooling by continuously active fishes: clues to sleep's ultimate function /J. Lee Kavanau --What exactly is it that sleeps? The evolution, regulation, and organization of an emergent network property /James M. Krueger --Evolutionary medicine of sleep disorders: toward a science of sleep duration /Patrick McNamaraandSanford Auerbach --Primate sleep in phylogenetic perspective /Charles L. Nunn ... [et al.] --Abird's-eye view of the function of sleep /Niels C. RattenborgandCharles J. Amlaner --Theevolution of wakefulness: from reptiles to mammals /Ruben V. Rial ... [et al.] --Theevolution of REM sleep /Mahesh M. ThakkarandSubimal Datta --Toward an understanding of the function of sleep: new insights from mouse genetics /Valter TucciandPatrick M. Nolan --Fishing for sleep /I. V. Zhdanova.