A trade magazine, also called a trade journal or professional magazine (and colloquially or disparagingly a trade rag), is a magazine whose target audience is people who work in a particular trade or industry. Its main goals are to keep members of the industry abreast of new developments (in which role it functions similarly to how  academic journals, scientific journals, medical journals, and engineering journals serve their audiences) and to serve targeted advertising to them, which earns a profit for the publication and sales for the advertisers while also providing sales engineering–type advice to the readers, helping them with industrial purchasing and investment decisions. The collective term for this area of publishing is the trade press (although that term sometimes also refers to publishers of trade paperbacks).