504 Absolutely Essential Words is divided into 42 lessons, each containing 12 new words. Those words are first presented to you in three sample sentences; ...

This carefully selected vocabulary collection is the essential core of words that need to be known and correctly used by middle schoolers, ESL students, and other adults for whom English is a second language. It presents 42 brief but effective word-building lessons. Each lesson introduces twelve new words contained in sample sentences and short articles. Fill-in-the-blanks exercises help students gauge their word-building progress.