Simile is known to be frequent in prose literature (Sayce, 1954; Goatly, 1997) and Carter (2004) found many examples in conversation. Given the long-traditional use of analogy by educationalists and the explicitness of similes, facilitating access to the concepts involved, we might expect to find frequent simile-type comparisons spread through educational discourse of all sorts, especially in the genres that are less formal in style than, say, research reports in academic journals. However, such appears not to be the case, to judge from previous studies of written text (Low, 1997; 2008). The present paper focuses on simile in spoken university lectures and builds on a study of metaphor in three lectures (Low, Littlemore & Koester, 2008), by adding a fourth, to give two conversational-style lectures and two more formal or rhetorical-style ones. The findings are that there are almost no similes at all in the data and where they do occur, it is only in the more conversational-style lectures. They rarely if ever form part of long rhetorical sequences, where the writer or speaker is offering an extended explanation. Rather they are one-off items serving immediate and short-term rhetorical purposes, what Conversation Analysts call ‘local control’, often associated with control of saliency and foregrounding at discourse level. (Publisher Book Description)