This post is part of a series on some of the most memorable companies that have disappeared.

Ah WorldCom. Aside from its storied history as one of the world's biggest accounting frauds, I remember it as my first cell phone company. My husband bought me a WorldCom phone as a gift and it turned out to not only have terrible service, but ridiculous billing practices, and we ended up paying to get out of the contract as I recall. I remember thinking that there was something really wrong with that company and later wishing I had pursued it as an investigative story, since I was then a writer at BusinessWeek Online and WorldCom was a hot stock.

But no, I never got onto such a story. In fact, I followed WorldCom's stock with interest since I had picked it in an office stock-picking contest years earlier and felt some satisfaction at its meteoric rise through the 1990s (even though I never actually owned the shares; it was just part of a fantasy portfolio).

But here's the WorldCom history that is worth remembering now: WorldCom started as Long Distance Discount Services (LDDS) in 1983. It changed its name to WorldCom in 1995. A series of mega-mergers transformed the company, culminating in its $40 billion deal for MCI. It was rechristened MCI WorldCom in 1998, the second largest long-distance calling company. The following year, just as it announced a deal with Sprint (now Sprint Nextel (NYSE: S)) that never came to fruition, the telecom industry started a prolonged downturn.

Cynthia Cooper was a true corporate whistleblower. She became famous, not by choice, but because of the WorldCom financial statement fraud valued at $11 billion. She was the Vice President of Internal Audit at WorldCom, a position that was not easily obtained. She almost single-handedly created the internal audit department at WorldCom, and her book Extraordinary Circumstances: The Journey of a Corporate Whistleblower details the struggle to get management to take internal audit seriously.

Things started going wrong at WorldCom very early. The company went on an acquisition spree, and the merging of many small companies, managers, and accounting systems was a disaster waiting to happen. Cynthia says that WorldCom was much better at acquiring companies than integrating them, and that is clear.

From an accounting perspective, it was next to impossible to create a properly controlled system. There were too many small systems being pieced together, and it was easy for numbers and authorizations to get lost in the shuffle. This struggle is well-documented by Cynthia, who no doubt painstakingly researched the various acquisitions in order to give such a complete history.

At times the book seems to get a little off-topic as Cynthia goes through each player's background briefly. Honestly, that information isn't really relevant to the story and, while it was probably intended to make these characters relatable human beings, it really just serves to make the book longer than necessary. It prolongs the process of getting to the real heart of the story.