For a few shortyears in the 1970s, the unique music of Focus entertained the world. Builtaround the prodigious instrumental talents of Dutch masters Jan Akkerman(guitar) and Thijs van Leer (keyboards and flute), the band produced threeclassic hit albums in quick succession between 1971 and 1974, at the same timescoring two worldwide hits with 'Sylvia' and 'Hocus Pocus'. The latter piece isas ubiquitous as tunes from the 70s get, distinctive for Akkerman's famous riffand van Leer's bizarre yodelling. Musical and personal tensions between the twoled to a split in early 1976, but the band limped on without Akkerman until1978. An unlikely revival in 1985 was a false dawn, and except for a few publicappearances, the duo have not played together since.     Stephen Lambe's book guides the readerthrough the band's early history, dealing with all seven Focus albums from theera song by song, plus the eponymous 1985 comeback. It is an important pottedhistory of the band and an insight into the tensions which led to such acreative - if short-lived – peak. But the book also acts as an essential guideto the astonishing music the two men made together – and sometimes apart -while at the apex of their powers.