business letters: body of the letter

The body of the letter contains the message. Here, more than anywhere else, the general principle of communication applies: say it clearly and succinctly, so that the reader will understand the message properly and quickly. Letters are normally single-spaced, with one blank line left between paragraphs. If a letter is very short, it may be double-spaced. When double spacing is used, the first line of each paragraph must be indented. Avoid writing paragraphs of more than ten lines. By the same token, do not divide a letter into many very short paragraphs.