"Not Western Africa, the Sahel Region or the Horn of Africa" takes out most or half of sub-Saharan Africa's population down to WW1: equatorial and southern Africa may have been a better wording.

Basil Davidson (a man of the left, and writing from a clearly Africanist perspective) offers many provocative studies of the region's history from the "inside", with which he enjoyed great sympathy.

In a similar vein is the mammoth Unesco General history of Africa, which surveys each region through the eyes of regional or topic specialists.

A more traditional take is the similarly enormous Cambridge history of Africa, still a must after several decades and organised along similar lines though with a more western perspective associated with its earlier creation.

As for post-colonial polities, they were overwhelmingly the result of European-designed boundaries: sometimes these followed geographical divides, often not, occasionally scything through peoples. Post-colonial border adjustments are few, the borders that were bequeathed having been widely accepted as the safest basis for nation-building.