I was sad to hear that author William Zinsser had died. Although he was in his nineties, it always unfortunate to lose a person who has had an impact on so many people.
The first book on writing that I ever read was his On Writing Well. Whenever I ask people what books on writing they recommend, his book is always the first on the list. If you have not read it yet, go and get a copy.
Here is the writeup in the New York Time on his passing.