PALPA has been designed as a comprehensive psycholinguistic assessment of language processing in adult acquired aphasia. Intended both as a clinical instrument and research tool, PALPA is a set of resource materials enabling the user to select language tasks that can be tailored to the investigation of an individual patient's impaired and intact abilities. The detailed profile that results can be interpreted within current cognitive models of language. The materials consist of 60 rigorously controlled tests of components of language structure such as orthography and phonology, word and picture semantics and morphology and syntax. The tests make use of simple procedures such as lexical decision, repetition and picture naming and have been designed to assess spoken and written input and output modalities. Particular attention has been paid to practical use of the tests in the clinic and comprehensive guides have been included that help to suggest which selection of test may be appropriate for each aphasic person. Each test is also accompanied by detailed instructions of how and why it was constructed, how to use it, and by presenter's forms and marking sheets.