One of the most powerful features of Bayesian analyses is the ability to combine
multiple sources of information in a principled way to perform inference. This feature can
be particularly valuable in assessing the reliability of systems where testing is limited. At
their most basic, Bayesian methods for reliability develop informative prior distributions
using expert judgment or similar systems. Appropriate models allow the incorporation of
many other sources of information, including historical data, information from similar
systems, and computer models. We introduce the Bayesian approach to reliability using
several examples, and point to open problems and areas for future work, including:
    - 
    Reliability for various types of systems: on-demand with pass-fail testing
    (notional SDB-II data) and continuous lifetime data (viscosity breakdown
    times). These examples include definitions and illustrations of prior
    distributions, likelihood and sampling distributions, posterior distributions, and
    predictive distributions.
- 
    Additional discussion of how to specify prior distributions is provided, along
    with brief descriptions of methods and possible resources for more complex
    analyses like hierarchical modeling, system reliability with subsystem or
    component level testing, and implementation using Markov chain Monte Carlo
    techniques.
- 
    Finally, some open research areas are discussed regarding combining
    information across multiple tests for assessment purposes and to plan an
    appropriately sized follow-on test.