There is growing interest in the ecology of the Maya Forest past, present, and future, as well as in the role of humans in the transformation of this ecosystem. In this paper, we bring together and re-evaluate paleoenvironmental, ethnobiological, and archaeological data to reconstruct the related effects of climatic shifts and human adaptations to and alterations of the lowland Maya Forest. In particular, we consider the paleoenvironmental data from the Maya Forest area in light of interpretations of the precipitation record from the Cariaco Basin. During the Archaic period, a time of stable climatic conditions 8,000–4,000 years ago, we propose that the ancestral Maya established an intimate relationship with an expanding tropical forest, modifying the landscape to meet their subsistence needs. We propose that the succeeding period of climatic chaos during the Preclassic period, 4,000–1,750 years ago, provoked the adaptation to settled agrarian life. This new adaptation, we suggest, was based on a resource management strategy that grew out of earlier landscape modification practices. Eventually, this resulted in a highly managed landscape that we call the Maya Forest Garden. This highly productive and sustainable system of resource management formed the foundation for the development of the Maya civilization, from 3,000 to 1,000 years ago, and was intensified during the latter millennia of a stable climatic regime as population grew and the civilization developed. These strategies of living in the forest evolved into the milpa cycle—the axis of the Maya Forest garden resource management system that created the extraordinary economic value recognized in the Maya Forest today.