Universities are trending towards displacing traditional printed textbooks (p-books) with electronic textbooks (e-books), even though an incomplete body of knowledge exists about the learning value of using e-books as instructional materials. As a result, this dissertation study was conducted to determine if digital textbooks are as instructionally efficient and effective as printed textbooks for e-learning using Sweller's (1988) cognitive load theory as a theoretical construct to investigate the effects on learners' cognitive load. Two groups of community college students (N = 52) participated in either an e-book treatment group (n = 26) or a p-book comparison group (n = 26). Participations read one book chapter and then took one posttest as a performance measurement to assess near-learning transfer. An online survey was conducted to gather self-perceived mental effort ratings and other variables of interest, including attitudinal, demographic, and usage factors. Posttest scores and online survey results were assembled. Frequency distributions and percentages were computed and analyzed. Independent samples t tests were conducted to compare the mean performance scores of the two groups. Cohen's d was computed to determine effect size. No significant difference was found between the e-book group and the p-book group relative to mental effort. However, performance differed significantly across book type; p-book users had significantly higher posttest scores than e-book users. Mental effort rating scores and performance scores were transformed to z scores and then applied to instructional efficiency and instructional involvement formulas. No significant difference was found between the e-book group and the p-book group relative to instructional efficiency and instructional involvement. However, after controlling for time on task in an ANCOVA, book type was significantly associated with performance; e-book users had significantly lower posttest scores than p-book users. Participants in the e-book group also experienced more eye fatigue (tired eyes) than the p-book group. Based on the results, it could be concluded that reading instructional materials from the p-book is a more effective instructional condition than reading from the e-book, because reading from the printed textbook produced a more significant effect on the near-transfer of learning for this group of participants. Future research recommendations are made. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]