is asynchronous, it's non-blocking! fs.readFile('README.md', ’utf8', function(err,data){ // Hello, Callback if(err) { console.error("Could not open file %s", err); } console.log("File read successfully” + data); }); // This is synchronous. It's blocking! var data = fs.readFileSync('README.md', 'utf8'); // This might take a while. Waiting, waiting... console.log(data); non-blocking i-what?