In addition to research in peer-reviewed academic journals, Okolie has been the sole author of several books. In 2004 he published a book called Political Behaviour, published by the Academic press in Enugu.[1] With the same publisher in 2005 he wrote Statistics for Political Data Analysis.[1] Okolie was a coauthor of Law, Politics and Mass Media in Nigeria in 2004 and Politics of Development and Underdevelopment in 2017.[1]
Okolie has also edited several volumes, largely focusing on the politics and political development of Nigeria. In 2009 he was an editor of Contemporary Readings on Nigeria's External Relations: Issues, Perspectives and Challenges. He also edited the 2014 book Politics and Law in Africa: Current and Emerging Issues, the 2015 book Norms and Practices of Global Political Economy, and the 2016 volume Governance, Economy, and National Security in Nigeria.[1]
Okolie's work and analyses have frequently been cited in the Nigerian press. His commentary on topics like elections in Nigeria, Nigerian political development, and international relations have been quoted in outlets including Nigeria's The Guardian,[6] The Blueprint Newspaper,[7] Vanguard,[8] Premium Times,[9] and The Abuja Inquirer.[10] Okolie has also consulted for state and regional governments in Nigeria, studying for example the fairness of Nigerian elections and the efficacy of the State Accountability and Voice Initiative.[11]