The epistolary war between Yahoo and Carl Icahn continued with a new Yahoo missive that details Icahn’s efforts to triangulate between Yahoo and Microsoft, who off and on for more than four years have been discussing some sort of deal between them.

The letter, signed by Yahoo Chairman Roy Bostock and CEO Jerry Yang, essentially makes the case for shareholders to vote for the company’s official slate of directors, rather than for the slate compiled by Icahn. The vote is scheduled for Aug. 1.

Bostock and Yang reminded investors of Icahn’s history of buying into companies and then making short-term maneuvers that temporarily pump up the value of the companies’ stock, but in the long term sacrifice their health.

They also tell a story of Icahn’s machinations, describing how Icahn agitated for deals that were, Yahoo alleges, already dead (with Microsoft) or were in the process of being consummated anyway without Icahn’s help (with Google).

Bostock and Yang paint a picture of Icahn flailing about, changing his objectives, not always consistent with his stated aims.

For all that, Yahoo said it remains open to a deal with Microsoft, provided the deal provides what Yahoo contends is an actual – rather than promised – value for stockholders.

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