Firstly let me tell you how much I'm enjoying your book! I'm learning so much and it's filling in all these gaps in my head regarding electronic circuits. I'd taken some classes on electronic circuits when I was a teen, but much of that has long since escaped my brain. You succinctly and clearly describe everything that's going on in each lesson without over simplifying the concepts.

I'm up to lesson 28 and 29, but it looks like the edition that I have is missing the latter half of lesson 29. I'm getting ready to build the oscilloscope probe in lesson 28. The last sentence in lesson says that the scope probe will be used in lesson 29, but lesson 29 goes for a page and a half, and then there's a page and a half of blank space, and then lesson 30. There's no mention of using the probe or the oscilloscope software! Am I missing half of lesson 29? If so, is there anywhere on the web where I can download the missing text?

Thanks for your time and congratulations on a great book!
Best regards,  Henry 

WOW! I just took a quick look at that. Yes, it does appear that something is missing. And better yet, I can't blame the publishers. That appears to be my mistake. I know why I missed it as well. I do this small part with my students on real scopes. So they missed the opportunity to catch that error of omission. 

My intent was to revisit question #9 on Page 90. That would give a person a visual of what is happening in the circuit when the oscillation is faster than what the DMM can follow. You can probably figure that one out by yourself. Don't wait for me. The black clip to ground and the red clip to a wire from the output at pin 10. Do this without anything else connected to pin 10. Then do it with the speaker. Then with the transistor and speaker in place. You will see how the load (the speaker) actually changes the shape of the signal. 
I could easily fill in the rest of page 103. 

Also, the probe works only on AC. As you will see, the slower the oscillation, the crappier the signal appears. This is because the sound card is protected from outside current by a coupling capacitor (Part IV, lesson 53 pg 209) . And yes, it is a very thin application for all the work put into making the scope probe. But it is used extensively in Part IV. As well, though I don't direct people to do so, I expect they will use the probe as they poke around in Part III. 
 
Dave C.