Rolling bearings are the most important machine elements. Proper functioning of a machine depends on condition of bearings. Vibrations help in diagnosing various faults in machines. Therefore, vibration based condition monitoring is the most popular method to know health of any machine. However, as found from the literature, vibration monitoring and diagnostics of faults in tapered roller bearing is not well established. This book is therefore focused on vibration based condition monitoring of tapered roller bearings. It presents results of experiments performed towards diagnosis of defects in tapered roller bearings using vibration analysis. The bearing vibration data are analyzed using various time and frequency domain techniques. The results for defect-free and defective bearings are compared to get information for defect diagnosis. A MATLAB based computer interface, which was developed for vibration signal processing and diagnostics, is also discussed in the book. This interface made use of all the time and frequency domain vibration data to diagnose defects in bearings. This book will be useful for the practicing engineers and students working on condition monitoring.