Brian Butterworth is Emeritus Professor of cognitive neuropsychology at the Institute of Cognitive Neuroscience at University College London, UK.
Brian Butterworth has been a leading researcher in the field of dyscalculia for a number of years... Butterworth's book contains a great deal of useful explanation of the different types of number sense which would be essential for anyone considering assessing for dyscalculia. - Janet Desmet MDG, Dyslexia Review