This would be a great book, if only it wasn't so fraught with errors. For example, p15 shows equation for 'mechanical lever' to actually reduce the output force from a given input force - this force would actually be increased greatly over the input force. While the text otherwise indicates this correctly, the transposing of smaller diameter symbol with larger diameter changes the meaning.
Unfortunately, there are too many more errors in the book to mention here, as space doesn't allow. A frustrating read, not reliable for an everyday reference. Hopefully an errata, or 'mea culpa' new edition will come out soon. Not worth the price of admission currently - don't buy this one!