... I found that I was unable to explain the foundations of quantum mechanics in a way that I found entirely satisfactory. - Steven Weinberg

Plücker's student J. W. Hittorf... observed that solid bodies... near a small cathode would cast shadows... [and] deduced... the rays travel... in straight lines.

Maybe at the very bottom of it... I really don't like God. You know, it's silly to say I don't like God because I don't believe in God, but in the same sense that I don't like Iago, or the Reverend Slope or any of the other villains of literature, the god of traditional Judaism and Christianity and Islam seems to me a terrible character. He's a god who will... who obsessed the degree to which people worship him and anxious to punish with the most awful torments those who don't worship him in the right way. Now I realise that many people don't believe in that any more who call themselves Muslims or Jews or Christians, but that is the traditional God and he's a terrible character. I don't like him.

In 1999 I finished my three volume book on the quantum theory of fields (..."QTF"), and... set... the task of learning... the theory underlying the great progress in cosmology in the previous two decades. ...Review articles ...gave good summaries of the data, but ...often quoted formulas without ...derivation, and sometimes ...without reference to the original derivation. Occasionally the formulas were wrong, and extremely difficult for me to rederive. ...[O]riginal ...articles sometimes had gaps in their arguments, or relied on hidden assumptions, or used unexplained notation. Often massive computer programs had taken the place of analytic studies. In many cases... it was easiest to work out the relevant theory myself.
This book is the result. Its aim... self-contained explanations of the ideas and formulas... used and tested in modern cosmological observations.