The quantitative analysis of molecular interactions is of high interest in medical research. Most methods for the investigation of ligand-receptor complexes deal with huge ensembles of biomolecules, but often neglect interactions with low affinity or small subpopulations with different binding properties. Single-molecule force spectroscopy offers fascinating possibilities for the quantitative analysis of ligand-receptor interactions in a wide affinity range and the sensitivity to detect point mutations. Furthermore, this technique allows one to address questions about the related binding energy landscape. In this article, we introduce single-molecule force spectroscopy with a focus on novel developments in both data analysis and theoretical models for the technique. We also demonstrate two examples of the capabilities of this method.