Full meaning of NCTB is National Curriculum and Textbook Board and this is regulated by Bangladesh Education Board. This part is handled by Bangladesh Ministry of Education and all rules and works are controlled by BD Govt. Every year Bangladesh Ministry of Education provides free books to students and that are hard copy and also this system NCTB provides soft copy of these books in these days. The soft copy of book is in pdf formet. So you can easily access these books on your pc or mobile phone.