I try to pack light. I'm often surprised by the large fraction of the weight from guidebooks. The guidebooks all seem to go for glossy pictures on dense paper. Even Rick Steves has succumbed to this. For example, for this trip: 'Pocket Florence' weighs in at 7.9 ounces (nearly half a pound); Italian Phrase Book & dictionary: 7.6 ounces (again almost half a pound). That makes almost a pound between them for thin 6x4.5 inch and 5.5x4 inch tomes. That's at least twice as dense as typical mass market paperbacks. I can try to strip out extraneous material from them, but it won't make much difference.
If you are serious about packing light, these are ridiculously heavy. You get glossy pictures, sure, but if I want that, I can buy heavy glossy guides for reading at home. For travel, I want light, light, light and small, small, small volumes. Black & white on thin stock works fine.
I'm sure Rick Steves' company is responding to market pressure, but please consider lighter weight alternatives. I *don't" need color pictures or maps. B&W/grayscale works perfectly well. Travel guides have limited useful lifetimes, so they don't require dense archival quality paper. In fact, Rick encourages ripping up his guides for trip-specific purposes. If the guide is printed on dense, heavy, glossy stock though, you still end up with an excessively heavy package.