Who invented the cereal bar?

There isn't a single, definitive "inventor" of the cereal bar. It's more of a gradual evolution of ideas:

* Early versions: Cereal bars likely emerged from a combination of ideas around granola bars and breakfast cereals. Granola bars were popularized in the late 1800s/early 1900s, while breakfast cereals gained traction in the early 1900s.

* 1960s: The Quaker Oats Company is credited with introducing the first widely popular cereal bar, called "Quaker 100% Natural Granola Bars," in 1969.

* 1970s-1980s: More brands and flavors emerged, including Kellogg's Special K Bars (1977), Nature Valley Granola Bars (1975), and PowerBars (1986).

* Present: Cereal bars have become a massive industry with a wide variety of flavors, ingredients, and nutritional claims.

So, while Quaker Oats may have a strong claim to the "first" widely popular cereal bar, it's a product that evolved over time through the contributions of many companies and innovators.