We have come to the end of our story. To leave it on the brink of quantum mechanics and its subsequent development is tantalising, but to take it further would result in a book aimed at a different audience and would need more advanced mathematical tools. How far I have succeeded in the many aims I set myself at the outset is not for me to judge. I can only state that, in preparing the original lectures and revising and amplifying them for publication, I have learned so much that I wish I had known long ago. My overwhelming impression, after 40 years of studying physics, astrophysics and cosmology, is an enhanced appreciation and admiration for the physicists and mathematicians who worked out the basic laws in the first place. These are outstanding intellectual achievements with flashes of genius and insight that raised the whole discipline to a new level of understanding.

On reading many of the original papers, I was impressed over and over again by the clarity of many of the great papers in the development of classical and modern physics. To be honest, I have found reading the original papers by physicists such as Maxwell, Rayleigh and Einstein easier than many modern textbooks. In these great works, I find a clarity of thought and exposition, which results from a clear understanding of the relation between our physical world and the mathematics we need to describe it.