Book Authoring Software
In the old days, authoring a book was a laborious proposition. The process of writing words on a page may have been relatively easy (even in the days of typewriters), but the process of submitting your work to an editor and publisher to have it professionally proofed and authored was an ordeal, to put it lightly. Today, with software like Scrivener, the ability to create written work from drafting all the way to final formatting is easier than ever, with your hardest challenge now being the actual writing process itself. All is as it should be!
Scrivener
Typewriter. Ring-binder. Scrapbook. Scrivener combines everything you need to craft your first draft, from nascent notion to final full stop.
Manuskript
Open-source tool for writers. With outliner, character management, plot development, distraction-free editor, etc.
Storybook
Discontinued
The project is no longer developed since 2008.
Storybook is a free, open source novel-writing software for creative writers, novelists and authors which will help you to keep an overview of multiple plot-lines while writing...
Writer's Cafè
A powerful but fun writers environment that includes the StoryLines structuring tool, a notebook, journal, writing quotations, scrapbook organiser, a 60-page e-book and more.
True Novelist
Writing a novel is a large undertaking. True Novelist was created to make the process as easy as possible for authors.
Novlr
Online word processor and organizer for novel writing. Includes detailed, novel-specific statistics, chapter reorganization, and the ability to export your novel.
FreeWriter
A full featured novel writing suite with unique features to help organize ideas and reporting.
Pagefour
Discontinued
The program is no longer updated. Last version, 1.87, released in October 2014, can be still bought from the official website.
Windows software for novelists and creative writers. A tabbed word processor, outliner, and organizer all in one.
Novelize
Novelize is an online novel writing app designed to keep authors on track. It can be used on any device.
A Novel Idea
Discontinued
The app is no longer updated. Last version, 1.15.2, released in August 2014, can be still downloaded from the Appstore.
A Novel Idea is a tool for plotting your story and recording bursts of inspiration.
StoryMill
Discontinued
The program seems to be no longer updated. Last version, 4.0.5, released in November 2011, can be still bought from the official website.
Storymill is a creative writing tool geared towards book writers; although, it could easily be used for other big creative writing projects, like scripts.
The Novel Factory
The Novel Factory is software specifically designed to help in every aspect of novel writing, from conception to publication.
Storyline Creator
Storyline Creator is an elegant tool to write stories ranging from short stories to novels.
Character Story Planner
This app is intended to be used for novel planning, particularly character development.It features a list of detail for the user to fill in.
StoryShop
A story planning app for writers: build worlds, develop your characters and create story beats.
Auteureist
Auteureist is a "novel" writing application for the Apple iPhone. Can export to some desktop software, like 
Scrivener .
Dabble
Craft your story. Write your novel. Dabble is software for writing novels for the desktop (Mac and Windows) and browser, syncing between computers.
Persona by Mariner Software
Persona is a character creation and organization app for writers. What makes the app unique is its sorting system: the user can match each character with an archetype in order to compare multiple characters at once to see how they might interact.
Novelist
From Google Play:> Novelist is the app that helps you writing your novels. And it's completely free: no initial cost, zero advertising and no in-app purchases!
World Scribe
World Scribe eases the creation process by letting you keep track of every important element in your fictional setting, including the ways in which they're connected.