Since man was created, he realised that his fingers were his best tools. He built his counting system on those fingers with which he learned to develop writing, writing the numbers and the alphabet. Our concept of numbers is born with us before that of speech and writing. The brain is conscious of numbers from the very early stages of development. This concept progresses with education, practice, and applications, i.e., through life experiences. Our life journeys, from beginning to end, go through a path totally surrounded by numbers. We adapt ourselves through this journey to make some sense of it. Hence, numbers are a major and essential part of our existence. This book highlights the history and development of numbers and delves into the mystery of number 9 in a wide variety of mathematical excursions. The famous Fibonacci numbers, as well as other numbers and sequences, fall under the mystique of number 9.