Regarding grammar books. I can recommend one small book that will answer most of your questions: The Plain English Guide by Martin Cutts.
Also try these:
Writing, Researching, Communicating: Communication Skills for the Information Age
The Elements of Style (4th Edition)
Style Manual: For Authors, Editors and Printers
On the internet just type in “grammar” and you’ll be inundated with sources of free information.
But the Martin Cutts book is excellent. My brother bought 100 copies and gives one to every new employee in his PR company and sends them to job applicants who write him grammatically incorrect letters (serves ‘em right!).