For many of us, the holiday season brings happy times with family and friends. Unfortunately, the season also brings a surge of substance-related car accidents. In recognition of the role that alcohol and other drugs can play in dangerous driving—by impairing perception, judgment, motor skills, and memory—the government and some private organizations have designated December National Impaired Driving Prevention Month. Consequently, The BASIS is dedicating the month of December to the complex issue of impaired driving. STASH and The DRAM will highlight recent research related to the predictors and consequences and drugged and drunk driving. The WAGER and ASHES will illustrate how other potential objects of addiction—gambling and smoking, respectively—have their own unique relationships with impaired driving. We hope you will enjoy and learn from this Special Series.