Abstract: An autonomous robot and methods are provided for lifting and stacking packages, such as on a shelf in a warehouse. The robot comprises a base, an elevator assembly that raises and lowers an elevator platform, an engagement mechanism for attaching the robot to a shelf, and steerable drive mechanisms for driving the robot in any direction (e.g. both forward and laterally) on a warehouse floor. The robot is navigated to a storage location of a package. The robot is driven laterally towards the shelf without rotating the robot or elevator platform, and is then clamped to the shelf. The elevator platform is then raised to the height of the package. The package is moved from the storage location to the elevator platform with a gantry.