Ethiopia lies close to the northernmost limit of the Intertropical Convergence Zone, where even a slight weakening in the strength of the monsoon may lead to rainfall failure. Being located on this sensitive climatic boundary explains in part why the country has such a long and infamous history of drought and famine. Understanding the past variability in the strength of the monsoon is critical to enable the validation of climate forecasting models. Late Pleistocene and Holocene environmental and climatic changes are reconstructed from two contrasting lakes in the highlands of Ethiopia: Lake Tana, the source of the Blue Nile, and Ashenge, one of the northernmost lakes in the eastern Sahel. An 18,700-year record from Tana is examined using mineral magnetic, X-ray fluorescence (XRF) spectrometry and diatom analyses. High-resolution XRF, stable isotope, and diatom analyses are utilised to produce a 17,200-year record from Ashenge. Of particular interest to this study is the timing and nature of the sub-millennial abrupt drought events. This book should appeal to anyone with an interest in African climate change past, present and future, as well as in the history of the Nile.