This document summarizes a seminar presentation on brain computer interfaces (BCI). It begins with an introduction defining BCI as a technology that aims to build a direct channel between the human brain and a computer. It then outlines the BCI model and discusses early work involving decoding brain signals in monkeys. The document reviews different BCI approaches including invasive, semi-invasive, and non-invasive methods. It lists several applications of BCI such as assisting disabled individuals and enhancing devices. Current BCI projects like BrainGate and gaming controls are examined. The conclusion emphasizes BCI's potential for rehabilitation and improving human performance.