Reports show that many thinking based curriculum have not been successfully implemented, mismatch between intended and implemented curriculum persists. This book explored how four secondary school master teachers involved in curriculum review internalized and taught using a new thinking science curriculum. Based on inquiry onto their understanding of the curriculum and observation of their teaching, the writer explored how they planned and created thoughtful classroom. Content of this book is based on finding of a qualitative case study using Strauss & Corbin''s coding procedure and the Paradigm Model with constant comparative technique. Detailed explanation of research design, methodology, instrument, validity, reliability, with-in case and cross case analysis is provided. The book also recorded the writer''s working experience in creating a thinking based curriculum. This book can be used by curriculum developers to improve the process of dissemination, guide teachers to discover their conception of teaching. The cases of teaching described will add to the reservoir of knowledge on practice of teaching to be used by teacher trainers and others.