In this chapter the nature of practical work is discussed in relation to some specific examples. The innovative work of the Assessment of Performance Unit (APU) in science, mathematics and English language is particularly highlighted as a guide to recent research in the assessment of practical work. The APU booklet for teachers gives examples of different kinds of mathematical activity that may arise within each kind of practical work. The General Certificate of Secondary Education (GCSE) emphasis on practical, oral and problem solving activities, especially in coursework, will ensure a need to organise and manage a variety of practical work which may range from short tasks focusing on specific skills to extended projects involving a complete investigation or design/make/evaluate exercise. APU developments are indicating that the size and cost of the task of including practical and oral assessments in the GCSE is likely to be considerable if it is to be done properly.