My first literary attempt would have ended up as another incomplete project but for the interventionof Chief Joop Berkhout and his energetic young son, George Berkhout. The two publishing partnerspushed and encouraged me to complete a rough draft and then handed that over to two outstandingprofessionalswho polished and rendered my modest effort into a readable material. ProfessorIsmaila Abubakar Tsiga was my senior in Barewa College and FCT colleague who offered to help doan initial review of the draft. His experience as an author, public servant and teacher substantiallyimproved the context and content of the book. This was further sharpened and made clearer by theawesomeediting skillsof SafariBook'seditorialmanager,SeniPinheiro.DeleOlojedethenundertookanotherreviewandeditingoftheimprovedwork.Ifthis bookturns outtobereadableandsensible, it is the result of the surgery done by Professor Tsiga, Seni Pinheiro, and Dele Olojede,even if all the errors remain mine. I thank them for trying to make a writer out of the appliedmathematicianthatIthinkIam!