When I was an intern, the Harriet Lane Handbook was my security blanket—I carried it everywhere. My new white coat soon bore the rectangular imprint of my constant companion, an imprint that proudly announced my growing status as a seasoned intern. I used the Handbook with almost every admission to the hospital, to write orders, check medication dosing, and confirm my differential diagnoses and management plans. When I became a junior resident, my relationship with Harriet Lane changed. The Handbook became less like my security blanket and more like a trustworthy friend. Although I didn't always need to have the Handbook with me, I did consult it for every major decision—checking medications, confirming formulas, or consulting tables and algorithms. And like any good friend, the Harriet Lane Handbook was a source upon which I could steadfastly rely.