Complex sentence: Mattick credited Marcuse with renewing "the endeavor to read Marx into Freud", following the unsuccessful attempts of Wilhelm Reich, and agreed with Marcuse that Freudian revisionism is "reformist or non-revolutionary".
Split into simpler sentences: Mattick credited Marcuse with renewing "the endeavor to read Marx into Freud", following the unsuccessful attempts of Wilhelm Reich. He agreed with Marcuse that Freudian revisionism is "reformist or non-revolutionary".