"Let's Think!" is a cognitive acceleration programme aimed at developing thinking in children aged between 5 and 6. "Let's Think!" was described in "PSR" 69 (Robertson, 2001) using the acronym CASE @ KS1, as it was known before publication by NFER-Nelson. Since then, "Let's Think!" has spread beyond the boundaries of Hammersmith and Fulham, West London, where it was devised and trialled. The programme is now taught in many areas of Britain and in other countries. It provides 30 activities for children as well as professional development for teachers, which involves three days out of class and in-class support. It is strongly recommended that teachers participate in this.