From the back of the book:
The first in a series of mecha manuals, MMM Vol. 1 contains 24 different mecha from nearly a dozen different background "universe." Covering power levels from basic war machines to star-powered world-smashers, the Mecha Manual demonstrates the amazing range of mecha which you can build and use in Mekton! Useful for adding new mecha to existing campaigns, it also shows how the background of your campaign can (and should) influence the nature of the mecha that populate it.
MMM Vol. 1 is compatible with both Mekton 2 and the upcoming Mekton Z. Each mecha comes with a full page illustration and game stats, as well as a short background essay on the fictional world that spawned it.