The present study analyzes the use of lexical bundles in first year core engineering textbooks, identifies vocabulary-based discourse units (VBDUs) in the textbooks, and further explores the connections between lexical bundles and the VBDUs. A first year core engineering textbook corpus (FCETC) of 995,672 running words was compiled with materials drawn from seven textbooks required for first-year engineering undergraduates at a Canadian university. A total of 95 lexical bundles were identified in the FCETC.Grammatical structure analysis of these bundles indicates that lexical bundles in the core engineering textbooks are more often phrasal than clausal. There are three functional categories of lexical bundles in the FCETC: referential bundles, discourse organizers, and stance bundles. The use of lexical bundles in the FCETC allows authors to take on the role of experts who precisely present and explain foundational knowledge and concepts in a professional way. These bundles also enable the authors to act as facilitators who make the content accessible for readers and involve them in the learning processes. The comparison of the use of lexical bundles in first year core engineering textbooks, electrical engineering introductory textbooks, university teaching, and university textbooks highlights the use of lexical bundles in these registers and suggests that disciplinary specificity and genres impact the use of lexical bundles in the four registers.The findings also support that vocabulary use is discipline bound in academic registers. A total of 665 VBDUs were identified in 14 chapters randomly selected from the FCETC.There are five main types of VBDUs, including explaining VBDUs, presenting VBDUs, solving VBDUs, introducing VBDUs, and bridging VBDUs. The findings of this analysis of VBDUs demonstrate that the authors of the engineering textbooks play dual roles of ii experts and facilitators but tilt more towards the role of facilitators. The author/reader relationships of the core engineering textbooks affect the structuring and negotiation of knowledge in these textbooks. The chapters in the engineering textbooks consist of sequences of VBDUs with various communicative purposes. Single or multiple VBDUs construct four types of macro-processes for knowledge construction, which suggest that academic textbooks do not only focus on concepts and theories but also the procedures and steps that learners need to follow to appropriately approach the theories and understand problem-solving operations. Further exploration of the relationships between lexical bundles and VBDUs shows that the communicative purposes of VBDUs determine the distribution of lexical bundles in these discourse units while the use of lexical bundles varies in categories and subcategories of VBDUs and helps achieve the communicative purposes of these discourse units. These bundles provide referential information on specific topics, indicate consideration for readers, and express authoritative stances in these VBDUs. This study contributes to the st...