I don't think i could even dare to read the book, in all honesty just watching the film and looking at the chalk boards had my head aching
Frankly "Brief history of time" isn't a very good book. Ok, if not great at the "known" stuff but Hawking rather mixes up wild speculation with solid physics which would mislead manu readers.
If you are after this sort of thing, then Einstein's own (popular) account of relativity (both sorts) and Richar Feynman's "Six easy pieces" are both superb, as is Bill Bryson's "History of Nearly Everything" Given he's a non-scientist, he has clearly talked to and learnt from, real experts (usually named) and done justice to their fields. Whilst only a gentleman amateur in such matters I can usually pick holes in popular science books, but on all the things I knew about in Bryson's book, it's spot on.