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Establishing text quality is often an important aspect of developing understanding both of writing processes and writing interventions. However, this concept of ‘text quality ’ is often not very well operationalized or described. The editors of this book state its aim as being to facilitate developments of a more precise understanding and definition of writing ability. The book comprises eight chapters that can be roughly divided into these topics: definitions of writing ability, rating procedures, rater effects and automated essay scoring. Definitions of writing ability In the first part of the book two chapters deal with the question: Is writing ability generalizable across contents? And, a related question, how many texts must be sampled from a student before something can be said about their general writing ability. In the chapter by Schoonen, he illustrates theoretical considerations about validity and generalizability by analyzing data from a large group of students at three moments in time, for three writing tasks in two languages. Schoonen states that for secondary school students 3 to 4 assignments, each rated by two raters, will be sufficient to make a general claim about a student’s written English as a Foreign Language ability. However, in L1 7- to 10 double-rated assignments would be necessary