Thogchags, also termed 'thunderbolt irons' or 'sky irons', are a special type of Tibetan amulet. From the Tibetan perspective, the objects, approximately 2 to 10 cm in size, have in the truest sense of the word fallen from heaven or have even been thrown from the sky by deities. Traditionally a thogchag must be found on or in the earth; according to oral lore, it lies at the point where lightning has struck. Thogchags are always of heavenly descent and command great powers of protection. With its comprehensive documentation of the diverse designs and forms of thogchags, the publication is an iconographic reference work on this extraordinary Tibetan amulet.