Welcome to Wikipedia,

the free encyclopedia.

Knowledge groups

	Mathematics Addition • Algebra • Calculus • Counting • Decimals • Division • Fractions • Functions • Geometry • Integers • Measurement • Multiplication • Numbers • Percentage • Prime Numbers • Rational Numbers • Subtraction • Statistics • Trigonometry
	English Adjectives • Adverbs • Authors • Grammar • Literature • Mythology • Nouns • Poetry • Public Speaking • Reading • Sentences • Shakespeare • Spelling • Verbs • Words • Writing • Vocabulary
	Fine Arts and Humanities Animation • Art • Art History • Books • Cooking • Customs • Culture • Dance • Movies and Films • Music • Philosophy • Plays • Psychology • Religion • Sociology • Theater • Travel • Television

Science Archaeology • Astronomy • Biology • Botany (plants) • Chemistry • Computer science • Earth science • Ecology • Engineering • Geology • Information Technology • Inventions • Medicine • Meteorology (weather) • Nanotechnology • Paleontology (fossils) • Physics • Transportation Zoology (animals)
History and Social Studies Africa • Asia • American Civil War • Canada • Economics • Ethics • Europe • Geography • Government • Japan • Laws • Military • Money • Politics • Russia • United_States • U.S. Constitution • U.S. History • U.S. Presidents • World History
Health and Fitness Baseball • Basketball • Fitness • Food • Football • Golf • Health • Hygiene • Nutrition • Running • Soccer • Sports • Sports • Tennis

Even though Wikipedia is an online encyclopedia, and even though editors are increasingly using online sources and e-journals, printed books and paper journals that are not available online are still a reliable source.