The 'Explanatory Dictionary of Russian Word Formation' is a first in the history of Russian dictionaries: it is the first dictionary which has information on affixes in Russian. It includes 1,892 morphemes (the smallest unit of meaning in a language) which function as word-building units in four parts of speech: nouns, adjectives, verbs and adverbs. The dictionary contains semantic descriptions of these affixes, and classifies them according to prefix, suffix and infix, also categorizing synonymous and homonymous relations between the affixes. This dictionary is intended for students and professors studying linguistics, pedagogy, or Russian as a foreign language at an advanced level. It can also be quite useful for anyone composing textbooks or grammar educational supplements.