In this paper I anlayze complex alternations which require an 
 intermediate representation between UR and output and therefore 
 appear to pose a serious problem for OT and other two-level theories 
 of phonology. I argue for the need for an intermediate representation 
 in OT and propose the Enriched Input model, which provides this 
 representation without creating a true three-level theory. An 
 intermediate representation is motivated by cases of compensatory 
 lengthening triggered by affixation as well as an opaque relationship 
 between epenthesis and deletion in Turkish, both of which require a 
 link between non-surfacing segments and syllable structure that is 
 not present in UR. The Enriched Input model provides a set of candidate 
 inputs of varying degrees of syllabification, all of which are required 
 to unify with the underlying representation. Candidate input-output 
 mappings are evaluated on the well-formedness of the input and output 
 and Faithfulness of the input-output mapping. The evaluation of 
 candidate input-output mappings is accomplished through use of a 
 tableau des tableaux of the type already proposed for Lexicon 
 Optimization. The paper concludes by showing how the Enriched Output 
 model can be applied to other types of opacity, such as the relationship 
 between vowel harmony, lowering, and epenthesis in Yowlumne (Yawelmani).
 This document is a handout prepared for TREND VII, held May 3, 1997 
 at UCSC.