Bayesian inference is a fundamental statistical approach that revolves around the concept of updating the probability for a hypothesis based on new evidence. It contrasts with frequentist inference by incorporating prior knowledge or beliefs about a parameter in the form of a prior probability distribution, which is then updated to a posterior probability distribution using the likelihood of the observed data. This method is particularly powerful in scenarios where the amount of data may be limited or incomplete, as it allows for the integration of expert knowledge or historical data into the analytical process. Bayesian methods are extensively used in numerous fields such as genetics, epidemiology, and machine learning, particularly in complex modeling and prediction problems where system parameters are uncertain.

Historical Overview: Bayesian inference is named after Thomas Bayes, who formulated the basic theorem in an essay in 1763. The method gained prominence in the 20th century, particularly after the development of Markov Chain Monte Carlo (MCMC) methods in the 1950s, which significantly eased computational challenges associated with Bayesian statistics.

Key Contributors: Thomas Bayes laid the groundwork with his theorem, but the modern Bayesian approach was developed further by statisticians such as Pierre-Simon Laplace, who expanded on Bayes' work in the 18th century. In the 20th century, figures like Harold Jeffreys and later, Andrew Gelman, played critical roles in the development and advocacy of Bayesian methods, particularly through their contributions to solving practical computational problems and in theoretical foundations.