The noted astronomer Carl Sagan and his wife married in 1968. In 1977, they signed a handwritten document entitled "Preliminary agreement, Marriage settlement," which contained property disposition and custody provisions. There was a subsequent handwritten addendum purporting to modify the preliminary agreement. It was never signed. Neither party adhered to the terms of the preliminary agreement. Subsequently, both Carl Sagan and Linda retained separate counsel. A separation agreement was drafted but not signed by the parties. The terms of the proposed separation agreement contained provisions significantly different from those of the handwritten document.