This study investigates the coherence properties of non-finite complements in Russian, Serbian/Croatian, and Macedonian. I demonstrate that Slavic non-finite complements do not project a uniform syntactic structure. The maximal projection of non-finite complements is not fixed but depends on the selectional properties of the matrix verb. I present empirical evidence that the size of non-finite complements varies according to [[plus or minus] verbal agreement] and [[plus or minus] mood/modality] and the syntactic structures based on Wurmbrand's (2001) restructuring approach, which has not been applied uniformly to Russian, Serbian/Croatian, and Macedonian. In Russian, all infinitival complements lack a CP. This claim is supported by empirical evidence from long-distance binding, long-distance NPI licensing, etc., which cannot take place across a CP. Subject Control verbs select a defective TP infinitive with PRO, which agrees with the controller by Multiple Agree, whereas object Control verbs select a Modal Phrase (ModP) with dative PRO. I argue that the source of the dative case on an object-controlled PRO is ModP. However, not all object Control infinitives project the ModP. Certain object Control verbs, such as "zastavit" "force", may select an infinitive without ModP, while others, such as "poprosit" "ask", select one with ModP. In Serbian/Croatian, infinitives do not project a ModP. They are TPs with PRO. But subject Control verbs, such as "zeljeti" "want", "odluciti" "decide", etc., are restructuring verbs in that they can be either raising verbs without PRO or Control verbs. Control verbs can also have da subjunctives, which project a CP and can have an overt subject. Subject Control verbs can be combined with either a "da" P that is smaller than a CP as a restructuring verb, or a "da" subjunctive. Macedonian subjunctive "da" clauses never project a CP. They are MoodPs, smaller than CP, and classified into two types. The first type can have an overt subject with a matrix verb, such as "posaka" "wish" and "moli" "ask". The second type has a PRO subject. Verbs such as "natera" "force" and "nagovori" "persuade" select this type of complement. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]