This is the classic West 1989 legal writing text. An updated - and, in my opinion, weaker - version of this is now the norm in law schools and small practices. This is a good guide to how to "write like a lawyer."
William P. Statsky is a graduate of Columbia Law School and is the author of 16 textbooks on paralegal subjects. Many of his textbooks, including “Introduction to Paralegalism,” “Torts” and “Family Law” are used in leading paralegal programs throughout the nation. Mr. Statsky is currently completing a series of individual state specific paralegal texts for students and practicing paralegals.