在網際網路普及率高居不下的時代裡，知識工作者平日使用網路之時間比例已有逐年升高的趨勢。在這種潮流下，工作場域中知識工作者花費於網路訊息傳播的時間，佔用工作時間之比率驚人，尤以電子郵件為甚。對於使用電子郵件所產生的問題，使用者似乎感到能力不足，而且在面對超載的資訊流通量時，更覺得難以應付。因為個人不佳的電子郵件使用習慣所引發的問題，都會直接或間接衝擊到時間資源的運用以及增加時間的壓力。因此，瞭解如何有效處理電子郵件，對於知識工作者的生產力非常重要。 本研究採用Creswell所提出之三階段混合方法探討研究議題。首先，第一階段採用質性之焦點群體訪談法，瞭解知識工作者典型的電子郵件使用行為。第二階段以大樣本的調查研究，探討知識工作者的人格主動性如何經由電子郵件管理行為影響其電子郵件使用時間控制感及工作時間控制感，並以社會認知理論及目標設定理論之整合觀點探討。第三階段以實地實驗的方式，在實際組織場域中進行員工電子郵件管理教育訓練，以觀察是否能產生訓練遷移之效果，亦即提升受訓者之電子郵件自我效能、電子郵件時間管理行為及電子郵件使用時間控制感。 第一階段焦點群體訪談的重要結論包括：1)使用者被電子郵件支配著，但他們往往毫無知覺；2)日常工作使用上，電子郵件的弱點卻變成其強項；3)具有資訊系統背景的使用者，不必然會使用電子郵件工具的複雜功能；4)電子郵件被認為是平面媒體，而非即時互動媒體；5)電子郵件在工作場合，已經大幅度地取代面對面溝通；6)電子郵件使用者習慣性地使用副本轉寄功能，但並非出於真正的需要；7)使用者並不常將工作或個人電子郵件分開處理；8)使用者非常珍惜學習電子郵件功能的機會，但機會並非輕鬆即能獲得。有關以上相關結論及看法間之對照情況也在本文中提及。另外，本階段也歸納出有效率使用電子郵件之方法，並據以發展下一階段調查研究法之問卷。 第二階段經由251位知識工作者之分析結果顯示，人格主動性透過電子郵件時間管理行為及電子郵件自我效能，可以推測電子郵件使用時間控制感及工作時間控制感。此外，電子郵件自我效能較高者，其電子郵件時間管理行為的評量分數也較高。 第三階段實地實驗共涵蓋280位受測者，其中實驗組有175位，控制組有105位。ANCOVA分析之結果顯示，相較於控制組，實驗組之受測者經過教育訓練後展現較高的電子郵件自我效能及較佳的電子郵件時間控制感，但是受測者於訓練後並未投入更多心力於電子郵件時間管理行為。此外，接受此電子郵件訓練課程一個月後，平均每一位受訓者節省約17%之電子郵件使用時間。 / At the high widespread rate of the Internet era, the time spent on the Internet among knowledge workers has gradually increased. Because of this trend, these people have spent an alarming proportion of their work time on message communications tools, such as emails. Problems arising from e-mail management make users helpless particularly when they have to deal with information overload. Problems caused by inefficient e-mail use would directly/ indirectly affect the time resource, inevitably increasing time pressure to the workers. Therefore, it is essential for knowledge workers to understand how to use e-mail efficiently to heighten their productivity. This study adopted Creswell’s three-phases mixed methods to investigate our research issues. First, this study investigates the e-mail usage behavior of knowledge workers through an in-depth literature review and a focus group discussion. Then, a sample survey method, along with a social cognitive theory and a goal setting theory, was adopted to investigate how personality affects perceived control of time in the context of e-mail handling. The third phase includes a quasi-experimental field study carried out in an organizational setting to examine the effects of an e-mail management training program on e-mail self-efficacy, e-mail-specific time management behavior, and time control over e-mail use. The important findings in phase one include : 1) people are ruled by e-mail, but they think otherwise; 2) in daily usage, many weaknesses of e-mail are turned into strengths; 3) an information system background does not necessarily lead to sophistication in using e-mail tools; 4) e-mail is regarded as a print medium rather than an interactive medium; 5) e-mail to a large extent replaces face-to-face communication in the workplace; 6) e-mail users use the carbon copy and forwarding features habitually and not out of necessity; 7) users do not usually handle work-related and personal e-mail messages separately; and 8) users seek opportunities to learn about e-mail functionality out of convenience, but these are not attained with ease. A contrast between these findings and conventional wisdom concludes this study. In addition, we also conclude efficient e-mail usage approaches in this phase and develop the questionnaire for the next stage. Based on data collected from 251 knowledge workers in second phase, the results show that personality predicts perceived control of time in e-mail handling and work through both e-mail-specific time management behavior and e-mail self-efficacy. In addition, higher e-mail self-efficacy leads to improved e-mail-specific time management behavior. The field experiment in third phase includes 280 subjects, with 175 subjects in the experimental group, and 105 subjects in the control group, the ANCOVA results show that, after the training, the subjects exhibited greater e-mail self-efficacy and better time control over e-mail use but not paid more attention to e-mail-specific time management behavior According to the study reported here, this employee training program leads to a perceived time saving of about 17%.