A Short overview:
Akzidenz Grotesk is often called the grandfather of all so-called “Grotesk” typefaces (German for grotesque- a way to name sans serif typefaces), the category of typefaces Helvetica falls under. Akizenz Grotesk itself was in a way a continuation of many other Typefaces that came before it, most notable Schelter & Giesecke's Grotesk, famous for it's Bauhaus use.
The swiss Haas typefoundry (controlled through German typefoundry Stempel and through it ultimately controlled by Linotype) in the mid 50s “refreshed” the design. Haas designed a new typeface based somewhat on the spirit and general shapes of Akzidenz Grotesk, calling it Neue Haas Grotesk. In a series of twits and turns between the differently interwoven foundries, technical specifications and international markets, it eventually ended up with the more marketable name: Helvetica.
Today, you can again buy a Font called Neue Haas Grotesk. Drawn from the original Specimen at Haas, you can read more about it in the A Future for Helvetica section.
Not really Helvetica...
Geniune Siblings:
Helvetica is certainly a very outstanding design: but it is not quite as unique as especially many fans in the United States may have you believe. Not only is it obviously related to it's ancestral AG, but Helvetica also has a prolific Sister, Adrian Frutiger's Univers, which shares much of the same ideas of Helvetica, but resolved them in a different way.
(You can see the similar horizontal terminals in both typefaces. Note the looser spacing in Univers and the different Lettershapes)
And a Love Child:
Other typefaces followed suit, and in the 1970, Haas typefoundry, the original creators of Helvetica, attempted to even release a typeface that caputured and combined the spirit of all these different faces, in something called Neue Haas Unica. Ill-fated due to problonged legal action, it was not until 2015 that a proper release could be made, arguably long fallen out of style and superceded by the onslaught of more modern, humanist sans serif typefaces like Frutiger, FF Meta or Myriad.
