Clear technical writing requires more than correct grammar: readers must also understand how ideas connect. This handbook approaches that challenge through four chapters on grammar, sentence structure, punctuation, and capitalization. Its examples come largely from research documents at NASA Langley, placing editorial decisions within the demanding language of scientific and engineering communication. The opening discussion distinguishes applying grammatical rules from revising sentences for greater effectiveness. It then examines possessive nouns, including joint ownership and possessives involving inanimate objects. Pronoun guidance focuses on identifying clear antecedents, maintaining agreement, and replacing vague references with more precise wording. Examples show how a seemingly acceptable sentence can leave readers uncertain about what a pronoun actually refers to. The handbook also considers first person pronouns in technical documents and demonstrates ways to avoid unnecessarily masculine wording. Its contents extend to verb tense, mood, voice, modifiers, prepositions, conjunctions, and dangling verbals. Sentence revision receives separate attention through clearer subjects, stronger verbs, parallel constructions, shorter wording, unambiguous comparisons, and deliberate emphasis. Later chapters organize punctuation by function and address capitalization in sentences, headlines, abbreviations, names, and scientific terminology. Throughout, the approach recognizes that authorities sometimes disagree and that editorial preferences are not universal rules. Writers, editors, proofreaders, and researchers can use the explanations and revisions to make informed choices about clarity and consistency in technical documents.