The Book of Songs or Poetry contains some of the oldest pieces of Chinese literature. It is said to have been compiled by Confucius himself, who has chosen out some 300 poems out of 3000. During the Former Han Dynasty, there were still existant four versions of the collection: in the states of Lu 魯 (by Shen Gong 申公), Qi 齊 (by Hou Cang 后蒼 and Master Sun 孫氏) and Han 韓 (by Han Ying 韓嬰), and the private collection of Duke Mao 毛公. Only the last has survived until now, the commentaries to the Han version have survived in the collection Han Shi Waizhuan 韓詩外傳.
The four divisions of the Book of Songs are the "Airs of the states" (Guofeng 國風), mostly songs of love and emotions, the Minor Odes (Xiaoya 小雅), partially with social critics, the Major Odes (Daya 大雅), concerning the praise of the Zhou Dynasty, and the Hymns (Song 頌), ritual songs of the house of Zhou 周, the dukes of Lu 魯 and the descendants of the house of Shang 商. All poems have a small preface (xiaoxu 小序), the first poem has a Great Preface (Daxu 大序). The content of these prefaces is a moral or even political interpretation of songs that surfacially seem to be simple love songs. The characteristic of these songs is that the initial verse creates a certain mood, in most cases using a picture of nature, birds or plants.
Almost all scholars of Han, Tang and Song wrote commentaries to the Book of Songs, because it was an integral part of Confucian teaching and had to be learned by heart by generations and generations of scholars.
The chapters of the Shijing are:

國風 Airs of the States　(for the location of the particular states, see also the map of Western Zhou) 周南 Airs South of Zhou (southern Shaanxi) 召南 Airs South of Shao (same location) 邶 Airs of Bei (southern Hebei) 鄘 Airs of Yong (southern Shanxi) 衛 Airs of Wey (southern Shanxi) 王 Airs of the Royal Domain (northern Henan) 鄭 Airs of Zheng (western Henan) 齊 Airs of Qi (Shandong) 魏 Airs of Wei (southern Shanxi) 唐 Airs of Tang (middle Shanxi) 秦 Airs of Qin (Gansu) 陳 Airs of Chen (southern Henan) 檜 Airs of Gui (northern Henan) 曹 Airs of Cao (western Shandong) 豳 Airs of Bin (middle Shaanxi) 小雅 Minor Odes 鹿鳴之什 The Decade Lu Ming 南有嘉魚之什 The Decade Nan You Jia Yu 鴻鴈之什 The Decade Hongyan 節南山之什 The Decade Jie Nan 谷風之什 The Decade Gu Feng 甫田之什 The Decade Fu Tian 魚藻之什 The Decade Yu Zao 大雅 Major Odes 文王之什 The Decade Wen Wang 生民之什 The Decade Sheng Min 蕩之什 The Decade Tang 頌 Hymns 周頌 Hymns of Zhou 清廟之什 The Decade Qing Miao 臣工之什 The Decade Chen Gong 閔予小子之什 The Decade Min Yu Xiaozi 魯頌 Hymns of Lu 商頌 Hymns of Shang

Examples of lyrics or songs each of the four sections. The first song of the Shijing is probably the most famous and most commented poem of old China. The Great and Small Preface to this song are translated too, as well as the begin of the Tang time Wujing Zhengyi 五經正義commentary.