Rechovot ha-nahar, Uri Zvi Greenberg's great book of lamentation over the destruction and loss of European Jewry, follows an ancient tradition of lamentation over the destruction and persecution of the Jewish people which has developed in Hebrew poetry since the era of the piyyut and medieval poetry. In this book Greenberg uses a new poetic language, including concepts and expressions such as kosef ('yearning'), nigun ('melody') and nofim ('landscapes'), which appear for the first time in this book but will reappear in other contexts in later texts. In this sense, Rehovot ha-nahar is a constitutive text, which introduces a new poetic and linguistic code.
The design of kosef as a central poetic code in the book is based on 140 occurrences and many variations of the term. Mapping of the appearances in the light of their various contexts and tracing their combination with or separation from fixed semantic clusters permits a different reading of the poems, leading to a complex world of meanings and spiritual modes, in a constant state of flux. The semantic shifts of the term kosef reflect the multiple aspects of human existence after the destruction of European Jewry.