What it is and the problem it solves
HTTP is an application layer protocol invented to support the WorldWideWeb project. It solved the problem of retrieving linked hypertext documents across a distributed network — without requiring shared state or prior coordination between machines.
How it works
HTTP is a request–response protocol in the client–server model. A client sends a request. The server returns a response. That response may contain an HTML document — and in 1990, it always did.
What works
The first implementation worked: client-server communication over the Internet succeeded in mid-November 1989. The first web server went live in 1990. It served HTML pages using only GET. That minimal exchange was enough to bootstrap the Web.
What does not
HTTP/0.9 supported only GET. It could not send data to the server. It could not handle images, forms, authentication, headers, status codes, or non-HTML content. It had no versioning, no error reporting, and no extensibility.
What it changes
HTTP established a universal, stateless, text-based interface for retrieving documents across networks. It turned the Internet from a collection of isolated tools into a navigable information space.
Is it worth your time
Yes — if you work with web systems, infrastructure, or standards. HTTP’s simplicity, openness, and lack of licensing lowered the barrier to entry for every subsequent web technology.