Franz Delitzsch wrote, A System of Biblical Psychology in 1855 and called it “one of the oldest sciences of the church.” Oswald Chambers published lectures in 1912 as the last definitive spokesman for Biblical psychology before secular psychology displaced it. This book traces seven stages of mankind from original creation to eternal glorification, and is for anyone interested in what God reveals in Scripture about human nature. Insights from 55 years of teaching Scripture and 35 years of clinical practice are synthesized. The content is scholarly enough for a textbook, but written simply enough for any serious reader. Theological principles are presented from the perspective of a mental healthcare provider, not case studies or personality theory. Heinroth, Delitzsch, Nee, and Chambers are introduced to terminal generation readers. Christ’s return is closer than ever, and the need to understand human behavior has never been more urgent!