Under the Skin is a highly ambitious, original and captivating novel about an exquisite bibliophile and possible serial killer, which tells an epic journey that begins in the German city of Weimar in 1918, with the story of patient zero of the most devastating flu pandemic in the history of humanity, and ends in the ruined Argentina of the nineties; passing through the rise of Nazism in Berlin, the persecution in Warsaw during World War II, the culture of New York in the sixties and community life in Israel, many years later.

The narrator, Jonathan Rosen – an American Jew of German descent – ​​begins the story at the age of twenty, when he moves to New York to study Literature at Columbia University in 1969.

At the same time that Jonathan falls in love in a Brooklyn bar with the woman he considers his "ultimate girl", he meets the enigmatic dandy, misogynist and manipulator Josef Eisenstein, thirty years his senior, who anticipates him in conquering the girl and ends up being Jonathan's teacher in the art of seduction through culture and intellect.

The novel tells how New York City lives fascinated by pop culture and at the same time horrified by the serial murders of very young women, dumped on the banks of the Hudson River and the East River by the "Williamsburg Skinner".

As time passes, Jonathan suspects that his mentor is hiding a very dark secret.

A chronological leap leads us to the disturbing and provocative story of Josef Eisenstein, born in Germany at the end of the second decade of the 20th century and whose characteristics – amoral, obsessive, possible murderer – remind us of other famous characters from great novels of German literature, such as the protagonists of The Tin Drum, by Günter Grass, and Perfume, by Patrick Süskind. Josef Eisenstein, through his story of desire and obsession, is equally original, controversial and unforgettable.

Critics also relate this book to The Truth About the Harry Quebert Affair, by the Swiss Joël Dicker.

Under the Skin, a work that brings together elements of the coming-of-age novel, crime fiction, war stories and psychological narrative, among others, is the first novel by the German writer Gunnar Kaiser.