For the most complete style guide possible, refer to the Chicago Manual of Style. Originally written in 1906 for scholarly book and journal authors published by the University of Chicago Press, the 956-page guide has also become popular among journalists and other communication professionals.
I enjoy using the 15th edition released in 2003, but the University of Chicago published the 16th edition in 2010. You can get it as a book or digital subscription.
Story: In 18 chapters and two appendices, the authors of the Chicago Manual of Style list guidelines for standardizing content, sources and grammar in various text types. This is the kind of book a copy editor uses to make sure that long works respect readers.
Structure: Reads in bite-sized chunks like an encyclopedia.
Style: American spelling, terms and traditions.