I undertake an analysis of themes and problems associated with the topic of intentional deception. I review the philosophical literature and try to clarify our moral intuitions. I motivate, explicate and test a new definition of lying. In Chapter 1,1 discuss the possible states of being deceived distinguished by Chisholm and Feehan in 'The Intent to Deceive'. In Chapter 2,1 consider, first, relative disvalue among these states; then, types of deceptive intent. In Chapter 3,1 question the assumption that an assertion is a special, solemn statement. I contend that standing behind one's words is intrinsic to the phenomenology of genuine assertion. In Chapter 4,1 show that to create an expectation in the deceived is not in itself to be ...