In this work I have included problem-solving in hidden Markov model, I also used codebook refining algorithm to test many human beings voice as a speech signal. Having been myself as a teacher in the field of electronics and communication Engineering, I have vast experience of teaching various courses in engineering college. I am sure that this book will enrich the students' knowledge of the subject. I strongly recommend this book to every Electronics and Electrical Engineering students and researchers and wish to a grand success.