Typical stuff about keeping things simple and direct。 Avoid longwindedness and passive words。Some revision on grammar issues。 Good for those who are trying to reduce the number of errors in business communications but not for those who are looking to improve their style。
Mohammed AlMatari,
The best book I read for writing formal messages。 Read it and practice what you read。
Mardin Uzeri,
Very useful reference; considerably improved my e-mail writing。