The trans activist and philosopher Julia Serano has written an excellent overview of the autogynephilia theory of Ray Blanchard, its history, its scientific flaws and its roots in traditionalist prejudices.
Crossdreaming is common
I joined the autogynephilia debate some 10 years ago, and have been trying to reduce the damages the theory has caused among gender variant people ever since.
I would say that one of the most important insights that have been brought up since then, is the insight that erotic crossdreaming or cross-gender fantasies are found among all kinds of people and not only among male to female "crossdressers" and gynephilic ("woman-loving") and bisexual transgender women.
You find cross-gender fantasies among cis people. You find crossdreaming among trans women who love men. You find it among many of those assigned female at birth. This alone falsifies the theory, which requires that only "straight men" (i.e. lesbian and bisexual trans women) have such fantasies.