From the introduction:
Lowell Was Right! is a role-playing game in which players take on the role of adventurous characters from one of the several inhabited planets in our solar system. One player will, instead of stepping into the role of a single character, be the Game Master. The GM plays all the minor characters in the game, creates scenarios for the players to respond to, and generally explain what happens when a character attempts something risky and/or dangerous.
Lowell Was Right! is not steampunk. All the scientific concepts in the game, like Ether and Gravitational Collapse, are science, not Science! It is set in the present day, just a very strange and different present day.
The original idea for this game came from the fact that what we think of as "Pulp" science fiction of the early 20th Century was based on fairly hard science concepts, concepts that the SF authors of the day learned in school, but those concepts were utterly changed before "Pulp" SF was written.
This game is based on a “What If?” question. “What if the science of the 1880s was basically correct? What kind of world would we live in now?” The name specifically refers to the astronomer Percival Lowell, who reported seeing canals on Mars through his telescope.
Lowell Was Right! is organized so that players get a sense of the world and then build a defining group concept, before proceeding to make individual characters. The book then describes the rules of play and outlines broader world concepts like the use of special technologies and starships, as well as diving deeper into the setting to look at the cultures of the solar system.