Sentences “padded out” with unnecessary words and phrases such as: actual, actually, even, even so, even still, still more, quite, just, really, clearly, indeed, whatsoever, in any way, now, itself, of course, but again, where on earth, how in the world, it stands to reason, so the question is, a good deal of, we can see that, it is a fact that, so it may not surprise you to learn that, in any way shape or form - and many others. Where practical, and where it didn’t change the meaning, I have removed such extraneous words and phrases. However, many remain because they reflect the author’s style of writing and I have neither the time nor the inclination to rewrite the book!

Spelling mistakes and strange, made-up words such as “re-enforced” instead of reinforced. I’ve corrected most of the errors but I’m certain to have missed a few.

Also... 

Incorrect use of words (wrong meaning). Incorrect use of apostrophes. Missing words. Repetition of words in the same sentence. Punctuation so random that many sentences made no sense. Confusing singular and plural in the same sentence. Illustrations incorrectly numbered.

There are also technical errors: confusing heat and temperature, confusing silica with silicon and silicone, and errors which appear to have been copied from another source without checking. Where I have noticed obvious errors, I have corrected (or questioned) them."