In this presentation, I review the theory, fabrication principles, and applications of bottle microresonators. The profile of a bottle microresonator (BMR) often resembles an elongated spheroid or a microscopic bottle. Generally, the shape of a BMR can be quite complex consisting, e.g., of series of coupled BMRs positioned along the fibre. The strong elongation of BMRs enables their several unique properties and applications, which are not possible or much more difficult to realize with other optical microresonators, e.g., those having the shape of a sphere or toroid. First, I will review the BMR theory including their spectral properties, resonant transmission of light through BMRs, and nonlinear BMRs. Next, I will consider the fabrication methods of BMRs. Finally, I will discuss the applications of BMRs for fabrication of miniature delay lines, lasers, and frequency comb generators, optomechanical microdevices, single photon microprocessors, and miniature optical sensors.