We review some recent advances in the field of magnetic manipulation techniques, with particular emphasis on the manipulation of mixed suspensions of magnetic and nonmagnetic colloidal particles. We will first discuss the theoretical framework for describing magnetic forces exerted on particles within fluid suspensions. We will then make a distinction between particle systems that are highly dependent upon Brownian influence and those that are deterministic. In both cases, we will discuss the type of structures which are observed in colloidal suspensions as a function of the size and type of particles in the fluid. We will discuss the theoretical issues that apply to modeling the behavior of these systems, and we will show that the recently developed theoretical models correlate strongly with the presented experimental work. This chapter will conclude with an overview of the potential applications of these magnetic manipulation techniques.