BioCyc is a collection of 7613 Pathway/Genome Databases (PGDBs), plus software tools for understanding their data. Tier 1 databases have received at least one person-year of literature-based curation, and are the most accurate. EcoCyc and MetaCyc have each received more than 20 person-years of curation.
Tier 2 and Tier 3 databases contain computationally predicted metabolic pathways, predictions as to which genes code for missing enzymes in metabolic pathways, and predicted operons.-From Publisher
Introductions to major writers, artists, philosophers, topics and periods. All are collections of specially commissioned essays, shaped and introduced to appeal to student readers. Together the chapters add up to a systematic critical account of, for example Plato, Luther, Jane Austen, Tom Stoppard or Stravinsky, the French Novel, Gothic and Romantic literature, or Jewish American Literature, and each title is supported by reference features such as a chronology and guide to further reading.
"Provides a complete overview of our nation’s past that covers the most-studied events, decades, conflicts, wars, political and cultural movements, and people. Comprehensive, contextual, media-rich information is provided on topics ranging from the arrival of Vikings in North America, to the stirrings of the revolution, through to the Civil Rights movement, 9/11, and the War on Terror."