Drawing upon research into the nature of the English writing system and about the development of spelling ability, this booklet presents an approach to improving spelling and vocabulary at the secondary school level based on a knowledge of the fabric of the language itself. The first section of the booklet reviews theory and research concerning the structure of English orthography, how people learn to spell, and orthographic implications for instruction. The second section explores word forms and letter constraints and the relationships between and among words, and discusses how new words enter the language and the importance of using a dictionary while proofreading to ensure correct spelling and consequently correct meaning. The booklet concludes with a selected bibliography for teachers and students. (HTH)