Timber framing is a way of building structures with large wooden members. It is very common in historical structures but has largely been replaced by the use of dimensional lumber (e.g. 2x4s). There are, however, groups and companies who still build timber frame structures today. If you are interested, I reccomend you check out the website for the Timber Framers Guild: Basic FAQs | Timber Framers Guild (tfguild.org). They have lots of books and other information to get you started. You should also search the web for a timber framing group near you. Getting involved in a build is the best way to learn.