This study focuses on the Atlantic Forest tree rats of the genus Phyllomys (Rodentia: Echimyidae), one of the most poorly understood mammal genera inhabiting the coastal rain forests Brazil, the most threatened lowland tropical forest in the world. The author summarizes their distribution, ecology and evolution, using a combination of morphological and molecular analyses, describes two new species, and provides the first systematic revision of the genus, which was originally described in 1839.