"Do so" anaphora is a fairly widely used in English, but has received relatively little treatment in the literature (especially when compared with verb phrase ellipsis). There are, however, two aspects of this anaphor that have gained prominence: (i) its use as a test for constituency within the verb phrase, and (ii) the semantic restriction it places on its antecedent. Though these two properties have been the most prominent, their analyses have not been uncontroversial. In this dissertation, I investigate these properties and give them a more complete analysis. The first part of the dissertation is devoted to a discussion of the use of "do so" as a test for constituency in the verb phrase, and the second part is devoted to understanding the semantic restriction that "do so" places on its antecedent. The behavior of "do so" anaphora has been used to argue both hierarchical structure (Lakoff and Ross 1976) and at structure within the verb phrase (Culicover and Jackendoff 2005). In chapter 2, however, I argue that "do so" does not have any bearing on the debate about the internal structure of the verb phrase. The arguments put forth by these authors are predicated on "do so" being a SURFACE ANAPHOR in terms of Hankamer and Sag (1976). Instead I argue that "do so" is in fact a deep anaphor and that its purported SURFACE ANAPHOR properties fall out from independent semantic and pragmatic properties of the anaphor. As a deep anaphor, "do so" does not replace any structure in the verb phrase, but rather forms a verb phrase in its own right from the beginning of the derivation. Therefore, the use of "do so" to argue for or against hierarchical structure in the verb phrase has been misguided. I approach the semantic restriction that "do so" places on its antecedent from two angles. In chapter 3, I review the previous analyses of this restriction, and test their claims against a corpus of over 1000 naturally occurring examples extracted from the American National Corpus. None of the previous analyses are supported by the data, and I present a novel analysis that utilize three semantic parameters (agentivity, aktionsart, stativity) to predict which antecedents are possible with "do so". One striking property of the counterexamples found in the corpus is that they instantiate particular syntactic structures. The majority of them contain "do so" in a nonfinite form (usually in the infinitive), and in others, the antecedent is contained in a relative clause modifying the subject of "do so". In chapter 4, I present experimental evidence that shows that these two syntactic environments lessen the effects of the restriction that "do so" normally places on its antecedent. I attribute this amelioration of the semantic restriction to the unavailability of verb phrase ellipsis in these syntactic environments. The analysis falls out from the nonmonotonic interaction of the two restrictions: the syntactic restrictions on ellipsis force the use "do so" to the detriment of the semantic restriction that "do so" normally places on its antecedent. I then situate this amelioration effect into the typology of coercion effects in general and argue that "do so" displays a novel type of coercion: subtractive coercion. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]