At left is the infamous Eversharp CA ("capillary action") ballpoint pen, which has been called "the pen that killed Eversharp". It has the styling of Eversharp's Fifth Avenue line. (The earliest CA pens looked like the Skyline series).
The modern ballpoint is descended from the pens made in the late 1930s by Hungarian Ladislo Biro (or László Bíró, to use the native spelling); when war threatened, he and his brother George moved their operations to Argentina, where they set up the Eterpen company. They registered their patent in the UK and in other countries, but not in the U.S., which would eventually lead to a legal conundrum. It seems that an Eversharp company executive "discovered" the Eterpen pen while on travel in Buenos Aires, and Eversharp was sufficiently impresssed to obtain a license to the Biro design; after a period of development, they introduced the CA in 1946.
Unfortunately, however, they were beaten to the market by a man named Milton Reynolds, who had also been to BA some time before, had also seen an Eterpen, and also was inspired create his own ballpoint; the Reynolds Rocket appeared in time to capture some Christmas 1945 sales (as documented in the film version of The Godfather). Unlike Eversharp, Reynolds had not seen fit to take out any licenses for the innovation, and so Eversharp was compelled to sue for its exclusive rights. The litigation took years to complete, by which time the case was pretty much moot. Even so, there was still room in the market for everyone, but Eversharp's CA pens, like other early ballpoints (including the Rocket), didn't work very well; this, combined with the company's inability to retune their thinking to the new age of cheap, disposable pens led to a steep decline in business
At $15, the CA was hardly cheap (it was, in fact, more expensive than the Parker 51); this reflects the early thinking that the ballpoint would be a newer and better (and hence more expensive) version of the fountain pen. Only later would industry realize that the ballpoint's real strength was that it could be made very cheaply and sold for prices much lower than the typical fountain pen.
While Eversharp made a number of pens during the 1950s, with names ranging from the sublime "Symphony" (from the studios of designer Raymond Loewy) to the ridiculous "Ventura Burp Pen", few of these are highly regarded by collectors today. The company was on its way out and had very little to offer. Eversharp was bought out by Parker in 1957; Parker used the Eversharp brand on a few pens (including versions of its new cartridge-filling 45), but eventually chucked it in. More recently, the Eversharp name and logo has re-emerged, applied to inexpensive ballpoitns and generic ballpoint refills (this has to be considered pretty ironic, given that the ballpoint pen was what got the company in trouble in the first place).
Vintage ballpoint collecting has recently emerged as a sub-hobby within the pen collecting field. You can often find the Eversharps or their contemporaries at shows, and books documenting them are beginning to appear. Unfortunately, unlike a vintage fountain pen, old ballpoints cannot be "authentically" restored to service because they are all dried up and replacement refills are generally unavailable for pens made before 1955 or so. However, some folks have figured out how to put modern pen refills into them (Bic stick-pen refills are favored for this transplant) so you can get them back writing once more.