Peter Lynch investigates volunteer organizations and rates them according to a range of verifiable criteria, including their scientific usefulness. Their credibility is assessed in terms of: accolades and endorsements, organization, financial records, evidence of environmental benefit and scientific outcomes. This updated guide includes long- and short-term opportunities from roughing it in tents, through simple permanent accommodation to quasi-luxury. First-hand accounts by volunteers provide insight into the day-to-day life of being a volunteer.