This paper presents an analysis of the introductory sections of a corpus of 20 doctoral theses on computing written in Spanish and in English. Our aim was to ascertain whether the theses, produced within the same scientific-technological area but by authors from different cultural and linguistic backgrounds, employed the same rhetorical strategies to introduce the work presented. The analysis follows the Swalesian approach and is based on a move/step/sub-step model proposed for PhD introductions in Spanish (Carbonell-Olivares, Gil-Salom, & SolerMonreal, 2009). The Spanish academic conventions appear to be that move 1 (M1-Establishing the Territory) and move 3 (M3-Occupying the Niche) are obligatory moves in PhD thesis introductions in Spanish, while move 2 (M2-Establishing the Niche) is optional. The structure of English thesis introductions reveals that they conform more closely to the M1-M2-M3 arrangement. Moreover, combinations of moves and patterns, cyclicity and embedding make their organisation more complex. The step analysis suggests that introductions in both languages rely mainly on the presentation of background information and the work carried out. However, the English introductions tend to stress the writer's own work, its originality and its contribution to the field of study. They also present more embedding and overlapping of steps and sub-steps than the Spanish texts.

Since the 1990s written academic genres have received considerable attention in discourse and rhetorical studies, especially texts written in English. Although few studies describe PhD theses as a genre, some work has been carried out on their macrostructure and the rhetorical moves of certain sections. In the Spanish literature, genre studies on academic writing are scarce relative to those in English, especially in the case of doctoral theses. We analyse the introductions of 21 doctoral theses in computing written in Spanish using Bunton's model (2002) for thesis introductions in English. The results indicate that most of the steps in this model are applicable to our corpus, but several new steps and sub-steps have been distinguished to account for the observed moves of Spanish PhD thesis introductions. The complexity of the thesis introduction is related to the scope and depth of the research carried out for a doctoral thesis, the need to display extensive knowledge of the field and to justify the relevance of the research.