Much of what is known about G6PD activity in Nigerians is obtainable from studies done in the 70s from the South-western part of the country. Very little academic information is available from the North-central region of Nigeria. Are there marked differences in the proportion of Nigerians with low activity of this enzyme from different geographic locations, and does it always translate to bad news when one is diagnosed of having G6PD deficiency? This book therefore provides new information about the activity and deficiency of G6PD in Nigerians resident in the North-central city of Jos,Plateau State of Nigeria, the problems associated with G6PD deficiency and how they present, benefits provided by the enzyme deficiency, what individuals who are G6PD deficient need to avoid and interactions of G6PD deficiency with other clinical conditions also very prevalent in our locality. The presentations and discussion should be useful to people pursuing a haematology course at the undergraduate and postgraduate levels,other medical professionals in tropical and subtropical regions, or anyone else interested in issues concerning G6PD.