There are only two roads that lead to something like human happiness. They are marked by the words: love and achievement.

Theodor Reik (1888-1969) Austrian-American psychoanalyst, writer

A Psychologist Looks at Love (1944)
    (Source)

Collected (with some modifications) in M. Sherman (ed.), Of Love and Lust Part 1, ch. 14 (1957).

This is frequently paraphrased or misquoted as "Work and love -- these are the basics. Without them there is neurosis." The apparent source of these misquotations is George Seldes, The Great Quotations (1960), where he attributed the passage to Reik and his book. Where Seldes got it from is unknown.

More discussion of this quotation: Ralph Keyes, Nice Guys Finish Seventh (1992).