This study examines linguistic deletion in Ibn Qutaybah's Adab al-Kātib. Deletion is treated as an established feature of Arabic and as a topic with a clear place in the classical linguistic tradition. The study defines deletion in its lexical and technical senses. It also identifies the main terms associated with it, describes its types and levels, and analyzes selected examples from the book. Particular attention is given to the close relationship between deletion and reconstruction (taqdīr). A deleted element is omitted from the linguistic structure, but a contextual or structural clue remains. This clue allows the omitted element to be recovered and preserves both meaning and grammatical coherence. The study considers deletion at the phonological, morphological, prosodic, and syntactic levels. It also examines deletion within the word and the sentence. Examples from Adab al-Kātib include the deletion of nūn in lam yakun to give lam yak, the deletion of alif in lam ubāl to give lam ubal, and the loss of weak letters in qul, biʿ, and khaf. The study also discusses the omission of sentence elements for brevity. It further examines the relation between deletion and iḍmār. In grammatical writing, iḍmār may be used in the sense of deletion. In other contexts, it may refer to concealment or an implicit element. The study concludes that deletion occurs in several forms and at several linguistic levels. Its use is governed by Arabic usage, attested speech, and transmission from Arab speakers. Frequent use, ease of articulation, and the avoidance of phonetic heaviness explain some of its forms. Deletion does not impair meaning when a clear clue identifies the omitted element. It therefore serves as an effective means of brevity and economy while preserving semantic clarity and structural well-formedness.