I think I would divide Currency into two categories: coin and paper. Many real civilizations invented somewhat standardized coins long before they had access to even primitive paper...I'm no expert, of course, but I'd allow people to branch off on tech trees like that...they may not want to move on to paper currency. Maybe they're perfectly happy carrying heavy pocket and pursefulls of coins everywhere they go. There is always the possibility of other forms of currency (nuts, beads, precious stones) as well as a bank note system for more advanced civilizations.

I'm unsure if a word exists that refers to the working of wood with metal in that way...have fun inventing one.

I thought about that...but felt I may have been getting a little off of the original writing tree just bringing up beads and stuff. You're right, though, he may not want to overlook the barter system...a people could just neglect currency altogether.

A lot of this kind of depends how far back we're starting this tech though...

Ter13 wrote:

Of course, I'm not too informed on the value of a goat in ancient times, goats aren't good for too much, just eating and breeding.

You forget - goats produce milk. Endless nutrition for practically free - after all, goats will eat just about anything, so feeding them is easy. =P

Well, to start with writing wasn't necessarilly first done on paper or papyrus. Their are ancient writing samples recorded in clay fragments inscribed with a stylus. Writing is generally thought to have first come about as an inventory and accounting system for the Phoenicians (there is evidence the Egyptians developed hieroglyphs for a similare purpose). So, historically, simple mathematics and writing are intricately linked.

Currency is essentially an evolution of barter, as pointed out earlier. Since barter gets unwieldy with large amounts of animals, resources, etc. humans find smaller, rare objects to trade instead. Eventually, the proxy items do not need to be inherently valuable and become representational (IE a nickel has no real worth). Paper currency is a later development that replaced specie (gold and silver currency) with bills. However, coins are still widely used and will continue to be for the foreseeable future.

The printing press is historically so valuable not just because it allowed the mass production of books, but because it spawned a new wave of literacy and publication. This would eventually lead to profound socio-political and religious changes.

Speaking of which, religion often plays a fundamental role is the establishment of societies. Not only is it a source of guidance and authority, it often leads to the construction of monuments and storage facilities. In some ancient cultures, for example, the temple doubled as a sort of granary where food was stored. Sometimes religion gives a place to those who have no other socially productive role. It is not uncommon for the elderly, deformed, or crippled to act as a priest, shaman or other spiritual leader. Indeed, some societies see deformation or ritual mutilation favorably.

Construction practices varied by region. Early hunter gatherers appear to have used highly mobile shelters such as hide tents stretched over a bone and wooden frame. Early agrarian societies usually develop masonry early on. Mixing sediments such as clay or mud, they are dried to produce a hard result suitable for building. As they advance, they stop constructing buildings wholly and digging out chambers and instead use molds to mass produce bricks for building. Roofing materials also vary by region, such as wood or thatch in vegetated areas or adobe or clay in more arid regions. As the socities advance, their building techniques usually get more sophisticated and the learn techniques such as kiln-firing to produce stronger ceramics and bricks, compositing techniques to produce mortar and cements such as Roman concrete, and engineering to produce larger more complicated structures by using forms such as the coloumn and arch.

If you are interested in these areas, I highly recommend you do some research in anthropology. Their is a wealth of fascinating information about humans and their developments over the last million and a half years or so.