The currency of Scotland is 'Pounds Sterling' with the symbol £. Each Pound is divided into one hundred pence.

The exchange rate varies. You can check the current exchange rate at this link > >
It can be useful to arrive with a little cash in local currency, even though debit and credit cards are accepted almost everywhere, and ATMs/cash machines are ubiquitous. You can usually order some cash from your local bank. For a slightly better exchange rate wait until you arrive and exchange at the airport or railway station in the UK.

Scotland is a little unusual with currency. There are different English pound notes and Scottish pound notes of many colors and sizes. Several Scottish banks are authorised to issue pound notes branded with their bank's name, so bank notes of the same denomination can look very different.  It can be a wee bit confusing.

If you use your credit or debit card on the trip, and a cashier in a shop, or a restaurant server, asks if you want the bill to be in dollars, say 'no'. Although it may seem counterintuitive, it will save you money to make your purchase in local currency, and let your bank or credit card company back home do the exchange from Pounds to Dollars. The exchange rate will be better and you will save money.

Light and Heavy Reading
These books recommended by Sunita and Fred are from their personal library, and are by no means exhaustive. It's a mix of historical tomes, novels, poetry, and travelogues. If you get through them all then you'll be well prepped for the trip.