Al-ʿUmdaẗ is an encyclopedia featuring ancient Arabic literary criticism; the rhetorical arts; genealogy and its foundations; the lunar mansions; place and country names; the sagas and deeds of the Arabs; the poetry of caliphs, judges, jurists, and writers; mercenary poets and its opposite, the poets' scorn for money; inspiration and technè in poetry; metrics, versification, and poetic themes: ġazal (love poetry), nasīb (love prelude), madīḥ (panegyric), iftiẖār (self-glorification), riṯāʾ (elegy), hiǧāʾ(palampooning); desirable attributes in poets; auspicious times for poetic composition; the various figures of rhetoric " istiʿāraẗ wa tamṯīl " (comparison and metaphor), " maṯal sāʾir " (aphorisms), " išāraẗ " (allusion), " kināyaẗ " (metonymy), " ramz " (symbol), " taǧnīs " (alliteration); "taqsīm" (distributions in poetry and prose), " istitrād " (digression), " iltifāt" (enallage/transposition), " ḥašw" (redundancy), " fuḍūl al kalām " (phraseology), " tikrār" (repetition), " wasf " (description), " istišhād biššiʿr" poetic quotations, " mā infarada bihi aššuʿarāʾ" (peculiarities of poets), " al maʾāẖiḏ ʿalayhim " what is reproached to poets, " assariqāt wa mâ chākalahā"; the various forms of plagiarism and other poetic thievery.
Also, this work represents a qualitative leap from the theoretical and methodological points of view. This is probably what made Ibn H̱aldūn say, "This is the only work that deals with this art and gives its right value; no one before or after him has equaled this book." Each of the parts of the ʿUmdaẗ, whether related to literary criticism, rhetoric, or history, is likely to intersect with another of its parts; for they all partake of what is known as the Diwān al-ʿArab (The Record of the Arabs).
Al-ʿUmdaẗis considered to be the crowning achievement of a literary and critical movement whose broad outlines became clearer during the second half of the fourth century of the Hegira and which fell apart with the sacking of Kairouan in 449 AH, when its remnants... moved to Sicily and Andalusia. This movement can only be understood in depth if we link it to the poetic movement created, among others, by Ibn Hānī and ʿAlī Al-Iyyādī, to the contribution of Qazzāz to the sciences of language, and to the contribution of Nahšalī and Ibrāhīm al-Ḥusrī to the discourse of literary criticism. While he devotes his ʾUnmūḏhaǧ az-zmān fī šuʿarāʾal-kayrawān (Model of Our Time: The Poets of Kairouan) to the poets of Ifrīqiyyaẗ, Ibn Rašīq in Al-ʿUmdaẗ refers mainly to the poets of the Mashreq, except for the quotations he makes from his own poetry and that of Ibn Abī Arriǧāl, his view of Ibn Hānī al-Maġribī, and the passages he reproduces from ʿAbdelkarīm Annahšalī et al-H̱ušanī Al-Qayrawānī.
Ibn Rašīq , as a sign of gratitude, dedicated his book entitled Al-ʿUmdaẗ (The Reference) to Abū Al-Hassān Alī Ibn Abī Arriǧāl from whom he quotes a number of lines of poetry in the chapter on the poetry of writers and in various other chapters.
