Lyme disease is caused by a bacterial infection transmitted by a tick bite, and is best treated early with antibiotics. However, many people suffer from chronic relapsing Lyme disease, which can cause a variety of physical and psychiatric symptoms: recurrent fever, fatigue, muscle and joint stiffness, poor coordination, lightheadedness, mood swings, and depression. In this User's Guide, health authors James Gormley and Caren Feingold Tishfield, R.D., explain how to best avoid Lyme disease and how to benefit from safe treatments.