I think Wizards made a huge HUGE strategic mistake with d20 Past. Aside from the book itself being a poor quality release (not just writing, but also size and in paperback) but I think they missed the boat on a potentially huge line of products. Were I in charge of the modern line at that point, I would have turned d20 Past into a line of at least 11 books, hitting every major time period. These would include:
d20 Prehistoric
d20 Ancient Times
d20 Rome
d20 Dark Ages
d20 Renaissance
d20 Age of Exploration
d20 Musketeers
d20 Wild West / Civil War
d20 Victorian
d20 Roaring Twenties
d20 World War II
For each book, I would include at a bare minimum, the following content:
Actual Real-world Timeline including major events, inventions, discoveries, catastrophes, wars, etc.
Linked Fictional Timeline including legends, myths, rumors, conspiracies, and similar supernatural events. (When added all together, the books could form one long official continuity)
Threat Countdown - listing major players (nations, churches, factions) as well as environmental threats like Black Plague
Fictional Countdown - same listing, but includes witches, dinosaurs, voodoo, or whatever else is appropriate to the era
Hot Spots - listing key adventure areas for the time period. Should include some regional maps, like the Middle East or Mediterranean during the Ancient Period and the Caribbean during the Age of Exploration
Danger Zones - around 3-6 battle maps of sample encounter areas, like a pirate ship or a civil war battlefield
NPC templates for common people of the era
Specific NPC's - for major real or fictional people of the area
Equipment - give us a real in-depth list for each era, with a price guide
Prestige Classes - at least a half-dozen per era
Occupations - one or two extra per era
Adventure Hooks - a standard list of 101 hooks per era
Special Rules - how to have a Wild West quick draw competition or similar custom rules
Special Advice - how to get the right feel for each era
At this point, you would have an easy 300 pg book, suitable for hardcover with a respectable price.
To me, as a fan of d20, I would probably purchase every one of those books. You could even set up an iconic set of time-traveling heroes to time them together, or maybe an iconic family tree. You could set up NPC groups and see how the evolve from book to book. You could encourage the adoption of these eras as official settings for the 3rd party publishers, and expand on any of them that really hit it off. I think there is no way this would not have been profitable.
Instead, what did they do? They released something like a 90 page softcover designed to cover the entire expanse of human history. They did a poor job of writing it, and they decided that its failure in the marketplace was an indication of waning interest in the entire d20 Modern line.
