As John Lange

Between 1966 and1972 Michael Crichton published eigtht novels under the pseudonym John Lange.

 
 

Easy Go (1968) would be republished under the title The Last Tomb in 1974, and Zero Cool (1969) was published with new material by Michael Crichton in 2008, shortly before his death.
Binary (1972) would be made within months of being published into a movie unde the title of Pursuit (1972).

  

The Eight John Lange Novels have been newly published as paperbacks on October 29, 2013, now with "Michael Crichton writing as...": http://www.michaelcrichton.com/books-medschoolyears-paperback.html . Note that the Zero Cool edition is the same as the 2008 John Lange edition, just with the author´s name ammended.

As Jeffery Hudson

In 1968 he published the novel A Case of Need as Jeffery Hudson. It would be made into the Movie The Carey Treatment (1972) and re-published under his own name in 1993.


   

As Michael Douglas

With his brother Douglas, Michael Cricthon wrote the novel Dealing Or The Berkeley-to-Boston Forty-Brick Lost-Bag Blues in 1970, under the pseudonym made by putting their two first names together. Playboy magazine published it in three installments in its December 1970, January 1971 and February 1971 issues.
It also became a film under the same title in ... yes, you guessed it: 1972.