The Bär Pistol is of German design, it was produced by Sauer & Sohn from 1899 until around 1914. It was never widely popular, which makes it rare in modern day, but for a short time it filled a small niche in the conceable self defense market. Because it had an overall profile that was thinner than most revolvers, it would lie flatter while carried in a pocket. Although it only held 4 shots, its capacity was equal or greater, than a comparative Volley pistol or Derringer. Most importantly, at the time of its design there were no mass produced semi-auto pistols which were of similar size, but soon that would all change.
When John Moses Browning's Model 1900 pistol was introduced to the European market by FN, the handgun industry would never be the same. Being the first successful mass produced semi-auto pistol, with a detachable magazine in the grip, was revolutionary. The Bär pistol was quickly becoming obsolete.
The true "nail in the coffin" for the Bär was in July of 1906, when FN introduced the Browning Model 1906. It was just as concealable as the Bär, more reliable, and far superior. Being semi-automatic with a detachable magazine capacity of 6 shots, and possessing greater safety features, which permitted pocket carry with a round in the chamber. The FN Browning 1906 quickly became the industry standard for vest pistols, and in 1908 Colt began making the same Browning design for the North American/U.S. market.
The Bär was first chambered for a proprietary 7mm cartridge, which was exclusively used in this pistol. But starting in 1906 Sauer began chambering the Bär in 25acp (6.35mm Browning) due to the rising popularity of the cartridge. However this adaptation was too little too late to save the Bär from failure, and by 1914 it is believed that the Bär pistol had ceased production.