The Pre-Test Basic Science Review series is designed to simulate the United States Medical Licensing Examination (USMLE) Step 1, which medical students take between their second and third years of medical school. These 500 question, answer and explanation books tap into students' examination anxiety - the questions allow students to hone their exam-taking skills, and the referenced answers/expanations provide students with brief, high-yield subject reviews. First and second year medical students are expected to know basic science facts and concepts and be able to apply them to clinical situations. The USMLE is becoming increasingly clinical in nature, and most questions have taken the form of clinical vignettes, integrating several subjects and emphasizing problem solving. Many require a "two-step" reasoning process. We plan to combine the genetics and biochemistry PreTests into one new, high-yield book; this first edition of "Biochemistry and Genetics: Pre Test" contains new questions in this two-step clinical format to more precisely simulate the USMLE Step 1. <br />