Careful and convincing enough to raise a curious legend from relative obscurity to the level of serious controversy, this is an impressively documented speculative study of a possibility: ""That it all happened just as set forth is unlikely; that none of it occurred seems equally unlikely. Too many people witnessed something."" Evidence is presented in turn for and against the existence of a Prince Madog (also styled Madoc); regarding one, probably two sailings westward; investigating the establishment of a Welsh-Indian lineage in America; about several subsequent searches for descendants perpetrated by variously motivated natives and foreign imperialists. ""The Strange Saga of John Evans"" recounts a peculiar perfidy -- treason, really, if indeed the Welsh explorer did withold genuine proof of such a colony because of a bribe by the Spaniards (anxious that their claim to discovery remain undisputed). Artist George Catlin's experiences with the Mandans yield more decisive cultural data favoring the thesis in question, backed up here by comparative vocabulary tables and specific references to early Welsh heritage (fishing practices, for instance, or the treasured blue glass bead ornament). Much emerges of incidental interest as well, particularly the commentary bearing on twelfth-century Celtic life (which bardic reports would be reliable and why, what seaports might have been departure sites, etc.) and on nineteenth-century research and expeditions; only the last chapter suggests unwonted fancy -- admittedly, however -- in postulating Madog's identity with Quetzalcoatl in Mexico (the emblematic Welsh Red Dragon resembles a plumed serpent. . . ). Thorough annotation, an extraordinary bibliography, and prints of old portraits and maps lend further credibility to a surprisingly absorbing chronicle prepared with great diligence and eschewing undue partisanship.