This article reviews the advancements in atomic force microscopy (AFM) in ultra-high vacuum, starting from its invention and covering recent developments. Dynamic force microscopy allows imaging of surfaces of conductors and insulators in vacuum with atomic resolution. Frequency modulation AFM (FM-AFM) is the most widely used technique for atomic resolution AFM in vacuum. The article explains the principles of FM-AFM, including the experimental setup, parameters, and physical observables. It discusses the challenges faced by AFM compared to scanning tunneling microscopy (STM), such as stability, non-monotonic imaging signals, long-range forces, and noise. The article also highlights the improvements in spatial resolution and ease of use achieved through empirical and theoretical advancements. Vacuum AFM opens new experimental possibilities, including imaging of insulators with true atomic resolution and measuring forces between individual atoms. The review covers early AFM experiments, the rush for silicon, and the development of FM-AFM, emphasizing its role in advancing surface science and materials research.This article reviews the advancements in atomic force microscopy (AFM) in ultra-high vacuum, starting from its invention and covering recent developments. Dynamic force microscopy allows imaging of surfaces of conductors and insulators in vacuum with atomic resolution. Frequency modulation AFM (FM-AFM) is the most widely used technique for atomic resolution AFM in vacuum. The article explains the principles of FM-AFM, including the experimental setup, parameters, and physical observables. It discusses the challenges faced by AFM compared to scanning tunneling microscopy (STM), such as stability, non-monotonic imaging signals, long-range forces, and noise. The article also highlights the improvements in spatial resolution and ease of use achieved through empirical and theoretical advancements. Vacuum AFM opens new experimental possibilities, including imaging of insulators with true atomic resolution and measuring forces between individual atoms. The review covers early AFM experiments, the rush for silicon, and the development of FM-AFM, emphasizing its role in advancing surface science and materials research.