This document provides an introduction and overview of various accelerated life testing methods, including HALT (Highly Accelerated Life Testing), HASS (Highly Accelerated Stress Screening), HASA (Highly Accelerated Stress Auditing), and CALT (Calibrated Accelerated Life Testing). It describes the basic principles, equipment, step stress approaches, benefits, and limitations of each method. The goal of these accelerated testing methods is to identify product weaknesses and failures earlier in the design process in a more time-efficient and cost-effective manner compared to traditional reliability testing.