Dirichlet series, or, series of the form D(A, s) = ∞ i=1 a i i s are central objects in complex analysis and analytic number theory. This paper seeks to generalize them by introducing & studying new types of Dirichlet series-quaternionic Dirichlet series, and lattice Dirichlet series. That is, Dirichlet series over quaternions, and, various types of Dirichlet series over lattices.