This little classic spends just short of an hour touring the Disney Studios in the company of Robert Benchley, the humorist who acts like a big kid in a candy store (and is thus the perfect guide for something like this).
We see how the cartoons are made, moving from the recording studio - where the real-life voices of Donald Duck and Clara Cluck sing an aria - through to clay models of the characters to be animated - the sound effects dept. (we see the full Casey Junior sequence, some of which ended up in 1941's 'Dumbo') - the scenario department (we see a whole cartoon - Baby Weems - in storyboard format) - the animation department (we see a cartoon feature on riding a horse, and see Donald Duck showing us how he walks) - and much more. There's also a neat segue from black and white to Technicolor.
'The Reluctant Dragon' is a book which Benchley hopes to pitch to Disney, only to find the film has already been made; the last 20 minutes of this feature is the cartoon about the (rather camp) dragon, and a classic bit of Disney work.
The whole movie is engrossing and a fantastic overview of the state-of-the-art work being done by the Disney Studios at the beginning of the 40s.