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.