This study examines sentence-level language abilities of amnesic H.M. to test competing theoretical conceptions of relations between language and memory. We present 11 new sources of experimental evidence indicating deficits in H.M's comprehension and production of non-cliche sentences. Contrary to recent claims that H.M.'s comprehension is unimpaired at grammatical levels, H.M. performed 2-6 standard deviations worse than controls matched for age, IQ and education in seven tasks: detecting grammatical errors, repairing sentences identified as containing an error, answering questions about who did what to whom in sentences, multiple-choice recognition of possible versus impossible interpretations of sentences containing ambiguities and figurative speech, discrimination between grammatical versus ungrammatical sentences, and describing the meanings of ambiguous sentences, phrases, and words. However, H.M.'s deficits were selective, e.g., sparing comprehension of familiar but not unfamiliar phrases. Parallels between H.M.'s selective deficits in language, memory and other aspects of cognition, e.g., reading and visual cognition are discussed. These parallels were predicted under binding theory but did not have a parsimonious explanation in systems theories that postulate non-overlapping units and processes for language versus memory. (Contains 2 figures, 7 tables and 6 footnotes.)