Over the years travellers kept diaries and wrote down what they thought about the places they visited. This can help us to understand what people thought about a place at that time.  
Old Newspapers tell us about the main things going on in a town or city. Aberdeen’s Central Library has old newspapers, which you can look at copies of. When an important event happened you can often find a newspaper report. It helps if you know the exact date otherwise you may have to look through a lot of papers!  
A report called the Statistical Account of Scotland tells us about towns and cities in Scotland. Some of these can be looked at on the internet - click here. People still write about Aberdeen now. There are lots of books about Aberdeen and its history in the public library and bookshops.