The partnership of the young and dynamic Daniel Barenboim with Otto Klemperer, a veteran not known for his readiness to compromise, proved a revelation. As Barenboim says, Klemperer - considered the greatest Beethoven conductor of his time - "approached the essence of what he wanted directly and without hesitation". The fruit of their collaboration in 1967 was this vivid and inspiring set of the Beethoven Piano Concertos.