When editing, there are 3 essential books that I frequently consult: a general fiction style guide, a local English style guide, and a relevant dictionary. Here’s a few details about each.
1. A general fiction style guide
The most universally consulted style guide for modern fiction is the Chicago Manual of Style (CMoS).
I have a physical copy of the 17th edition, which I frequently consult for every edit I do in American English. I also consult it if something isn’t mentioned in the local style guide I’m using, as CMoS tends to be more all-inclusive on certain topics.
If you love physical books like me, you can pick up a hardcover copy of CMoS online for around $120-150. Dymocks has it for $115. You can also subscribe to it online (though the rates change year by year), and get a 30-day free trial.
A lot of what’s included in CMoS is more geared towards academic and non-fiction publishing, but a lot of it also applies to fiction.
2. A local English style guide
When working on an edit in Australian English, I always check the Australian Government Style Manual (AGSM) first. If something isn’t mentioned or explained enough here, I then move on to CMoS.
The 7th edition of AGSM is free online and was never released in print. I also have a physical copy of the 6th edition (just because I love physical books), which I got second hand on Ebay.
Like CMoS, AGSM is also geared more towards non-fiction writing, especially government publications, but a lot of it also applies to fiction.
3. A relevant dictionary
I mainly work on edits in Australian English and American English. The dictionary I consult varies depending on which locality English I’m working in.
For Australian English, AGSM recommends using either the Australian concise Oxford dictionary (ACOD) or the Macquarie dictionary. AGSM itself uses ACOD, so I do also (I have a physical copy).
You can pick up a hardcover copy of the most recent and comprehensive version of Macquarie (9th edition) for $140 from Dymocks. The concise version comes in at $64.99, while the compact version is only $29.99. You can also get a yearly subscription to the Macquarie dictionary to use it online, which is a cool feature that I don’t think ACOD offers.
You can get the most recent version of ACOD (6th edition) from Dymocks for $59.95, but this is the concise version, so it won’t be quite as inclusive as the $140 copy of Macquarie.
For American English, CMoS recommends using Merriam-Webster, so this is what I use. It’s free to use online, though you can subscribe to gain access to more entries in the unabridged version.
Crossbones Editing 