The Apachian-Madrean region is a zone of confluence and geographic termini of species and floras from the north and the south. Lower and intermediate elevations support many taxa of tropical plants and animals that are at their northernmost limits. It is a region of tremendous habitat diversity and species richness. Much of the region remains little known, and quantified data are scarce. This report offers brief synopses on the insect fauna, ichthyofauna, herpetofauna, avifauna, mammals, and vegetation and flora of the region. The vascular plant flora is estimated to include approximately 4,000 species, although endemism is not particularly high. A partial listing of endemic plants numbers more than 250 taxa. Likewise there are approximately 250 wild relatives of domesticated crop plants. Land race diversity of native crops is richer than in any other American region north of the tropics. A brief economic assessment, descriptions of environmental threats and conservation measures are included.