His love poetry is generally considered to be the highest peak of his achievement as a poet. It was written between 1933 and 1939 and was published in "La voz a ti debida" (1933), and "Razón de amor" (1936). A third collection, "Largo lamento", was not published during the poet's lifetime, only appearing in full in 1971. For many years, it was assumed that these poems were rhetorical exercises - poems that use the techniques and devices of his earlier poems but focused on an imaginary love affair. Among the people who knew him well at the time, Cernuda thought that they were playful exercises, not seeing any great significance in them. Guillén, on the other hand, takes them very seriously but gives no sign that they might have been based in reality, real feelings. He even quotes the view of the critic Leo Spitzer that this is love poetry where the beloved is a phenomenon created by the poet, whilst asserting that this point of view is fundamentally mistaken. However, in 2002, Enric Bou published a set of letters sent by Salinas to Katherine R. Whitmore between the years 1932-47. She taught Spanish at Smith College, Northampton, Mass. In 1932, she spent her summer vacation in Madrid, where she met Salinas and they fell in love. A few weeks later, she returned to Northampton. She returned to spend the academic year 1934-5 in Madrid where they picked up their affair. However, on learning that Salinas's wife had discovered what was happening and had tried to commit suicide, she broke off relations. A sporadic correspondence continued afterwards but she married another man and the affair was over. The very shortness of the affair, two summers and an academic year, perhaps explains why it seems to have gone unsuspected by his close friends. The intensity of his feelings, however, are captured in the letters and, above all, in these collections of poetry. Guillén seems to have been the person who tracked down what had happened.