Double entry accounting has interesting features, which are rooted in three basic concepts—duality, balance (parity), and dual (double) entry. The first two of these concepts are so fundamental and pervasive that they are present in almost everything in existence, including economic (capital) resources and accounting transactions (events). The third concept is not as pervasive but unique to accounting. It is invented to guide how accounting events should be recorded based on their duality and balance features as the conceptual foundation. This chapter examines the features of double entry accounting in view of those three basic concepts and does so from the perspective of geometry. It does so by showing how double entry accounting works as a one-dimensional (debit-credit) geometry as it does in the traditional accounting-only approach. The chapter ends with a discussion of the limitations of the one-dimensional geometry, in view of the multidimensional nature of accounting events and the duality and balance features of double entry accounting.