Long articles should be split into a series, if possible -- each with a useful, short title. If this is impossible or undesirable, they can be maintained as a single article but split into segments (like splitting a chapter into pages, as opposed to splitting a book into chapters).

See, for the moment, Origins of the American Civil War, Isaac Newton (in depth);
In contrast, see, eg., History of the English penny, History of Brazil

TimS liked the latter one, so a quick analysis: Hist of Brazil is broken out into an overview page and N detailed pages. The overview page includes:

• A navbox at the top (linking to the N subpages)
• A "Related Topics" section at the bottom (linking to N+8 other pages, including the N subpages)
• A TOC which includes the names of the N subpages as toplevel sections
  • In each section, a summary of the related subpage, and an explicit link to the subpage in an italicized mini-header.

The subpages include detailed information, the N-element navbox, and an elaborate footer table linking to previous and next articles in the series (as well as their own "Related Topics" sections).

Elements to address

• Unified TOC in the top segment (forged, not automatic; abbreviated)
• Nav-links between the segments (at the top of each segment)
• prev / next links (at the bottom of each segment)
• Top-of-page intro paragraphs for each segment (above the TOC)
• Size of each segment
• Nesting segmented articles in a series or other nav-scheme (only show single link, unless looking at a segment of the art)
• Dealing with segmented Talk pages

philosophy on long arts

The central difference I see b/t a long article and a collection of detailed subarts is just like the difference b/t a single 5-paragraph article, and 4 1-paragraph stubs linked from a central 1-paragraph overview. There are differences in tone, in level of background given (when you have separate arts, you need to give more background for each one; common abbreviations have to be reintroduced each time and cross-refs relinked, etc), and in thematic flow (you can refer back to previous elts of a long story in different ways...). +sj+

Where appropriate, I like long articles -- the 'related topics'/external links/bibliography/ appear once, as it should be; navigation can be low-key and elegant, with "forward/back" links at the bottom of every page, as in a long e-zine article; and external links to the article can all be redirected to the first page. Finally, it then makes sense to have a single TOC for the entire article. +sj+