A Joker Story - "Definitive Therapy" was commissioned and paid for by DC Comics for an anthology called The Further Adventures of The Joker to tie in with the first Batman movie.

We as a race have spent millennia warring and killing each other over everthing from God to Country, Money and Power, Love and Jealousy, or even simple Psychotic Rage. But now that Humanity has a new enemy to face, one from the stars with far superior technology. And it is now up to every Man, Woman, and Child to come together and make a choice: fight for their Freedom, no matter the cost and to the bitter end, or Surrender and face the implications of what that means...

Can a troubled investigator rescue humanity from its mistakes? Bill Taggart lost his wife and his last spark of happiness on humanity's new home. Now as part of the team sent to monitor the indigenous aliens on Exilon 5, the investigator hopes to find a clue to explain her disappearance. But when official reports on the mysterious race clash with Bill's findings, he wonders just how many secrets the terraformed planet holds... This book was previously published as Becoming Human.