An ideal pathfinder on the Beatles' long and winding road from moptops to magi--insightful, informative, contentious, and as ambitious and surprising as its heroes. Popular music criticism is often a thankless task, falling uneasily between mindless hype and lugubrious academicism. MacDonald, former deputy editor of New Musical Express, adroitly bridges that gap, taking the factual chassis--recording session data, itineraries, etc.--laboriously assembled by Beatlemaniacs like Mark Lewisohn and bringing to bear a fan's enthusiasm, a musicologist's trained ear, and a critic's discernment to produce the most rigorous and reliable assessment of the Beatles' artistic achievement to date. Advancing chronologically through the songs, MacDonald provides an encyclopedic wealth of biographical, musical, and historical detail, yet always keeps his eyes on the prize--the uniquely rich elixir the group distilled from these disparate elements. He considers the Beatles on their own musical and cultural terms, taking his cue from contemporary influences (rhythm-and-blues, soul, and the supercharged social crucible of the '60s), rather than straining for highbrow parallels in Schoenberg or Schubert--you'll find no reference to the infamous ``Aeolian cadences'' of ``This Boy'' here. MacDonald makes no bones about his own critical convictions: He prefers the artful structures of pop, its ``energetic topicality'' that ``captures a mood or style in a condensed instant,'' to rock's ``dull grandiosity,'' a shift he attributes to a general retreat since the '60s away from depth and craftsmanship into spectacle and sensation. Accordingly, he champions the pop classicism of the Beatles' early-middle period, culminating in Revolver and Sgt. Pepper, and in his most memorably acerbic passages deplores the rockist leanings of their later work: ``Helter Skelter,'' for instance, is dismissed as ``ridiculous, McCartney shrieking weedily against a backdrop of out-of-tune thrashing.'' The ultimate Beatles Bible? Certainly a labor of love, and all the more valuable for holding the Fabs to the highest critical standards.