The book deals with the concept of Heavy Work Investment (HWI) recently initiated by Snir and Harpaz. Since its introduction the interest in the general HWI model has increased considerably. The book illustrates the development of HWI conceptualization, theory, and research. It deals with the foremost HWI subtype of workaholism. However, it also compares workaholism as a "negative" HWI subtype with work devotion/passion/engagement, as a "positive" HWI subtype. Most importantly, it addresses HWI in general, including its possible situational subtypes. In view of Snir and Harpaz's claim that the study of situational heavy work investors is relatively scarce, this certainly constitutes a promising step in the right direction. Finally, it deals with timely and important topics examined by prominent international researchers on Heavy Work Investment and such issues as: personality factors of workaholism, work-life balance, cross-cultural similarities and differences in HWI, work addiction and technology, HWI and retirement, and intergenerational similarity in work investment.