Clinics in Developmental Medicine No. 159The Gross Motor Function Measure (GMFM) is the first evaluative measure of motor function designed for quantifying change in the gross motor abilities of children with cerebral palsy. The measure is widely used internationally, and is now the standard outcome assessment tool for clinical intervention in cerebral palsy. This new version (GMFM-66) is completely revised, largely new, and has been improved through Rasch analysis. GMFM-66 transforms the standard GMFM into an interval measure; provides an 'item map' of the relative difficulty among items; and includes a user-friendly, computer-assisted software program to aid in scoring and interpretation of GMFM data. This is included, with a printed scoresheet, on a CD-ROM enclosed in the book. The expertise of the authors comprises paediatrics, design, engineering and physiotherapy. They have over years devised and run research at the CanChild Centre for Childhood Disability Research at McMaster University in Hamilton, Canada.