# Introduction

How can something so small be such a big problem for so many people? Yes, two little letters ... D ... T. Enough to bring grown men and women to their knees, swooning in fits of frustration and despair. But now, right here, we're going to fix all this. In this Chapter, you will learn almost everything you ever wanted to know about that deceptively tricky little rascal known only as ... "DT" (though Delta Time is the official name on the birth certificate).