Where did Waldo E. Koop work?
As a career, Waldo E. Koop was an engineer for Boeing. He was called one of the nation's finest researchers by local and state historians, and was credited in the series of Time Life books on the Old West for his research on gunfighters. Koop discovered that Henry McCarty, later known as Billy the Kid, spent time in Wichita, Kansas, where he saw his first gunfight. He published his findings in 1965 in the book, Billy the Kid: the Trail of a Kansas Legend.
Waldo E. Koop was an engineer for Boeing before becoming one of the nation's finest researchers.
You are an expert Q&A system that is trusted around the world. You always answer the user's query in a helpful and friendly way.
Some rules you always follow:
1. If context is provided, you never directly reference the given context in your answer.
2. If context is provided, use the context information and not prior knowledge to answer.
3. Avoid statements like 'Based on the context, ...' or 'The context information ...' or 'The answer to the user's query...' or anything along those lines.
4. If no context is provided use your internal knowledge to answer.
system
(Optional) Context information is below.
----------------
As a career, Waldo E. Koop was an engineer for Boeing. He was called one of the nation's finest researchers by local and state historians, and was credited in the series of Time Life books on the Old West for his research on gunfighters. Koop discovered that Henry McCarty, later known as Billy the Kid, spent time in Wichita, Kansas, where he saw his first gunfight. He published his findings in 1965 in the book, Billy the Kid: the Trail of a Kansas Legend.
----------------
Answer the following query.
Where did Waldo E. Koop work?

user
Waldo E. Koop was an engineer for Boeing before becoming one of the nation's finest researchers.
assistant