Dr. Santos mentions Norman Vincent Peale and his book The Power of Positive Thinking
(1952) as one of the earliest in this space. I might suggest that Napoleon Hill’s Think and Grow Rich
(1937) was a natural precursor to this and these ideas of visualizing what you want as a means of helping to get it. His work assuredly influenced Peale’s and probably sells as well today.
It takes what it takes.
–Bob Bowman, swimming coach of 23-time Olympic medal winning swimmer Michael Phelps
Hope is not a course of action.
–Kristin Beck, Senior chief petty officer, United States Navy SEAL, ret.
Gabriele Oettingen’s work and the Woop concept (Wish, Outcome, Obstacle, Plan) sound interesting. Perhaps worth reading some of her work:
Oettingen, G. (2015). Rethinking positive thinking: Inside the new science of motivation. Current.
“You name the goal, and research shows that positive thinking makes it less likely you’ll reach it.”
Oettingen, G., & Mayer, D. (2002). The motivating function of thinking about the future: Expectations versus fantasies. Journal of personality and social psychology, 83(5), 1198
Oettingen, G., & Wadden, T. A. (1991). Expectation, fantasy, and weight loss: Is the impact of positive thinking always positive?. Cognitive Therapy and Research, 15(2), 167-175
Oettingen, G., Mayer, D., & Portnow, S. (2016). Pleasure now, pain later: Positive fantasies about the future predict symptoms of depression. Psychological Science, 27(3), 345-353.
“It’s a strategy Gabrielle calls “mental contrasting.”
Oettingen, G., Mayer, D., Timur Sevincer, A., Stephens, E. J., Pak, H. J., & Hagenah, M. (2009). Mental contrasting and goal commitment: The mediating role of energization. Personality and Social Psychology Bulletin, 35(5), 608-622.
“In addition to simulating the obstacles, Gabrielle also recommends taking time to imagine— very intentionally— what it would feel like to implement our plan whenever the obstacle comes up.”
Oettingen, G., & Gollwitzer, P. (2010). Strategies of setting and implementing goals: Mental contrasting and implementation intentions (pp. 114-135).
Some of the ideas behind the WOOP concept remind me of some tangential sounding philosophy and framing that Matt Maldre wrote about in his recent posts about New Year’s resolutions.  
WOOP also seems tangential to some areas of memory research as the visualization can tend to create “false” memories that one can look back on as experience when moving toward a particular goal. I often found that in my diving practices in college I did significantly better on new dives when I visualized them or practiced them in my mind several days and even the night before practices.