you cannot but benefit from reading this book
As collator of the ACCU book reviews, I come across many of styles of writing, spelling and punctuation. I know that there is not one correct form for these aspects of writing, but there ought to be some firmish guidelines, so that you know when you push against one of the mores of writing English.
I enjoyed reading Eats, Shoots and Leaves; Lynne Truss has a very comical turn of phrase and I did learn a little about punctuation, but the lack of an index made it very difficult to use as a reference book.
The Penguin Guide on the other hand has not left my desk. While it does not have the humorous input, Trask writes very clearly with an eye to the detail of the issues under consideration, while at the same time making it easy to remember the points. Did you know there are four separate uses for the comma: listing, joining, gapping and bracketing?
There are many examples of good and poor punctuation on almost every page, with the poor examples flagged with an asterisk to remove any possibility of confusion or doubt. Having read the book from cover to cover, which is very easy to do, the four pages of index make this a really useful reference.
If you are writing (specifications, requirements, books, emails, letters) or editing the same, then you cannot but benefit from reading this book, after which it will find a cosy place sat next to your mouse and keyboard. Highly Recommended.