{{Short description|none}} The following articles contain '''lists of problems'''. This includes unsolved problems, which may refer to several notable conjectures or open problems in various academic fields:
==Natural sciences, engineering and medicine== * List of unsolved problems in astronomy * List of unsolved problems in biology * List of unsolved problems in chemistry * List of unsolved problems in geoscience * Unsolved problems in medicine * List of unsolved problems in neuroscience * List of unsolved problems in physics
==Mathematics== * List of unsolved problems in mathematics * List of undecidable problems * List of NP-complete problems * List of PSPACE-complete problems * List of problems in loop theory and quasigroup theory
== Social sciences, statistics, and information sciences == * List of unsolved problems in economics * List of unsolved problems in fair division * List of unsolved problems in statistics * List of unsolved problems in computer science * List of unsolved problems in information theory
==Other== * List of philosophical problems * List of unsolved deaths ==See also== * Cold case * List of ciphertexts * List of hypothetical technologies * List of paradoxes * Unknowability
{{unsolved problems}} {{list of lists|science}}
{{DEFAULTSORT:Problems}} Category:Lists of unsolved problems * Category:Science-related lists Category:Lists of problems Category:Engineering