Sometimes people will keep notes or things they see in the outdoors or keep a journal and paper getting wet and then wrecked is a big problem.
The other obvious use is printing maps off from the internet like the free USGS topo maps.
Is there a way to keep one's notes or journal or printed maps from getting wrecked by rain or water in general?
At the risk of stating the obvious...
... just not letting your paper get wet in the first place is by far the easiest and cheapest solution.
How you might ask? These solutions worked well for me in the past:
Use a map pouch for maps, papers, notes etc that you'll need to read often, but not edit/write on. There exist plenty of options, most are water proof and transparent.
Use any combination of plastic bags / dry bags / dry boxes depending on how water-proof the content must be. Personally I always bring some mini dry bags to store my notebook and the toilet paper.
For paper that needs to be read and written in rainy conditions I mostly used larger transparent plastic bags, that I could sort of put my hands inside and just write while my notebook/papers were still inside the bag (with the bags opening going to the side, not up). This is a bit improvised and doesn't work well in windy conditions, but did the trick on the rare occasions I had to take notes while out in the rain.
The solution to this problem is waterproof paper. You can get it in notebooks, journals, legal sized for printing maps or documents etc. I have also seen at least one organization that had their instructor manuals printed on it.
Some waterproof paper can be used with pencils, regular pens, and waterproof pens, while some only work with pens. The advantage of a pencil is that it won't freeze up in cold weather. Also, regular pens won't work when the paper is wet, but pencils will.
The downside, of course, is that they come at a higher cost than regular paper, but at the same time not having to keep them out of the weather more than makes up for it in my opinion.
You can find these by just searching for "waterproof paper", the best ones I have seen are the Rite in the Rain products.
One option is to laminate your paper. Normal lamination pouches aren't ideal. You need special pens for them, and they always fail at some point (usually when you need them). There are matte lamination pouches which are made for writing on. You can write on them with normal pencils (the only writing device that always works). The advantage is, that you can use it with any type of paper/printer. The disadvantage is, you need (access to) a lamination device.
When it comes to printing, there are printable vinyls for both laser and inkjet printers. Some inkjet inks run badly in the wet whatever the substrate, while others show little or no deterioration. Even on paper I intend to keep out of the rain, I prefer laser printing for outdoor use as it can try a little damp without being completely wiped out, and doesn't stain other items.
The downside of the vinyls (and many of the plastic waterproof "paper" products) is that they don't fold like paper. Also they're not recyclable or biodegradable and no use for starting fires.
I print gpx routes on openstreetmap mapping using a site called inkatlas, and just use normal paper, but in heavy rain in my toptube bag (on the bike) some water gets in the seams.
Waterproof Smartphone, there are several models with different tolerances available.
Electronic sources like, free USGS topo maps off from the internet, can be downloaded straight to the phone.
Notes can be made in text or voice recorder apps
Older original paper documents can be scanned or photographed
Before paper there was clay, papyrus, wood, slate and parchment, After paper there are electronics. The paper is medium for transporting recorded data.
Additionally I beleive you can download all the questions and answer from TGO
The ideal solution for maps is laminating them with acetate sheets. While managing without bubbles is somewhat of an acquired skill, it doesn't require a machine. They'll be nearly indestructible at the cost of being somewhat more difficult to fold. Best of all you can write on them easily with a permanent marker and wipe it off later with alcohol. (Fine point Sharpies and prepackaged sterile wipes work well.)
[ On a side note you ought to be using permanent inks or pencil regardless, because water based inks don't fare well after a swim. ]
Short notes you can put on the back or side of the map. Long form writing like a journal is best done out of the rain. If you need to do it regularly in the rain I'd get used to carrying a poncho or light tarp and a couple of bungie cords to allow instant shelter. Important information, like research notes, should be taken down on separate papers and transferred into the journal or notebook later in the safety of a reliable shelter like a tent or cabin. Don't be the guy who drops a notebook out of three waterproof bags into a puddle.
As far as protecting regular paper goes I'm fond of sandwich and freezer bags. Clear sandwich bags make a pretty decent "field expedient lamination device" for any information handed to you on small card stock that you may need to read in the rain. Freezer bags work well for notebooks. Both are a lot cheaper than specialty pouches and the fact that you discard them after saves wear and tear. Wrap the bag containing your book with a shirt or towel for extra protection and keep it inside the waterproof bag in your pack.
If you just want a memo pad that can be kept out of your pack the waterproof paper ones aren't awful. They do work and give you some protection against being submerged, but they're much less pleasant to write on than paper. Short of being required to take notes at a sprinkler research facility I'd opt for a hard-shelled waterproof case and regular pad. The biggest advantage of the waterproof pads is being flexible enough to be comfortable in a pocket.
The best solution is to not use classical paper. There are a lot of alternatives nowadays and you've already received a lot of them through the other answers.
However, the reason why I write yet another answer is that I have the ultimate solution for your problem as a whole: The Rocketbook Everlast (explanation video). I use it for myself at work, privately and of course while being out there as my field notes. It's really awesome!
Stone paper, you can find notebooks made of it on Amazon. they have brought out a range for chefs to use in kitchens is how I heard about them. Seem to be well reviewed.
