This chapter is devoted to the classic simultaneous localization and mapping (SLAM) problem and the related problem, bundle adjustment. In these problems we must estimate not only the trajectory of a robot but also the three-dimensional positions of many point landmarks, based on noisy sensor data and a motion model (in the case of SLAM). We discuss how to adapt the tools presented earlier to include landmarks in the state; the inclusion of landmarks changes the sparsity pattern of the resulting estimation equations and we discuss strategies of continuing to solve them efficiently. Our approach is carried out entirely in three dimensions using our Lie group tools.