This book, History, Theory and Philosophy of Okpe Igoru Music derives from a doctoral thesis submitted to the University of Pretoria, Pretoria, South Africa for the award of the Doctor of Music (DMus) degree. It is presented in three parts. Part one provided very brief information on the location and population of the Okpe in Nigeria and treated the historical development of igoru music. The author, in this part, traced the history of igoru music through periods classified into four, between c1100 AD and 2005. Part two investigated the philosophical thought processes involved in igoru musical compositions and performances. The author examined how igoru musicians follow and apply synthetic philosophy in ascertaining truth and meaning in human society. The third part dealt with the compositional techniques and theories of igoru music. It examined issues of scale system, theory of flexibility versus beauty and objective, theory of flexibility versus contextuality, theory of foundation vowel, theory of duplicative significance, etc. It also examined the peculiarities of its compositional and performance techniques as well as musical forms.