Conditionals encode speculation. They convey how events could have been different in the past or present, or might be different in the future if particular conditions had been or will be met. While all languages afford the means to speculate or hypothesize about possible events, the ways in which they do so vary. This work explores some of this variation through an analysis of the structure and semantics of complex conditional sentences in Russian and Macedonian. It addresses typological questions about the general properties of natural language conditionals and examines the role of the grammatical categories tense, aspect, mood and status in the coding of conditional meaning. The book also discusses the relationship between the use of these categories and the shape of a language's conditional system. For example, the use of tense in counterfactual contexts in Macedonian correlates with the grammaticalization of more shades of conditional meaning than are grammaticalized in Russian, which does not employ tense forms in this way. The book addresses issues of concern to Slavists and raises questions for those interested in conditionals and the coding of hypothetical meaning.