Background: The Comprehensive Aphasia Test (CAT; Swinburn, Porter, & Howard, 2005) was published in 2005, the first new aphasia battery in English for 20 years. Aims: We aim to describe the motivations driving design decisions in the development of the CAT, summarise data on its properties (reliability and validity), and consider reasons why it might be a suitable assessment for clinical use. Main Contribution: The test is designed to (1) screen for associated cognitive deficits, (2) assess language impairment in people with aphasia, (3) investigate the consequences of the aphasia on the individual's lifestyle and emotional well-being, and (4) monitor changes in the aphasia and its consequences over time. This lead article discusses the CAT's advantages over other aphasia batteries available. Conclusions: We argue that the CAT is based on the best available current theoretical knowledge about the variables known to affect aphasia performance, and gives as much information as is possible from a relatively short standardised aphasia battery for designing therapy plans, while also giving therapists information to make a prognosis when people with aphasia are assessed in the first few months after onset.