The underlying premise is that the greatest "miracle" is the act of simply gaining a full "awareness of love's presence" in a person's life.

Jampolsky's first book, Love is Letting Go of Fear, based on the principles of ACIM, was published in 1979 and, after being endorsed on Johnny Carson's show, sold over three million copies by 1990.

[19] Though a friend of Schucman, Thetford, and Wapnick, Catholic priest Benedict Groeschel criticized ACIM and related organizations.

Finding some elements of ACIM to be "severe and potentially dangerous distortions of Christian theology", he wrote that it is "a good example of a false revelation"[23] and that it has "become a spiritual menace to many".

[24] The evangelical editor Elliot Miller says that Christian terminology employed in ACIM is "thoroughly redefined" to resemble New Age teachings.

[4] Olav Hammer locates A Course in Miracles in the tradition of channeled works from those of Madam Blavatsky to Rudolf Steiner's[15] and notes the close parallels between Christian Science and the teachings of the Course.

[...] Since the Course’s redefinition of terms is so offensive to its critics, [...] the Gospel narrative that the Course subverts and redefines is the suffering, death, and crucifixion of Jesus.

[19]Another dismissal of ACIM and claim for its subversiveness comes from some on the political left, who note that William Thetford, who encouraged and helped bring Schucman's work to press, was a CIA operative and psychologist.

In Harper's Magazine, Sheila Heti quotes a post asserting the CIA sought "to infiltrate and dilute the American left with New Age ideas and inwardly-focused, anti-rational religious movements".

Two works have been described as extensions of A Course in Miracles, Gary Renard's 2003 The Disappearance of the Universe and Marianne Williamson's A Return to Love published in 1992.