If you were popped out of the timestream and found yourself suddenly in the distant past, how much of our modern technology could you re-create? I've often thought that I could climb back to the vacuum tube era of the 1920s or so.
Author H. P. Friedrichs has realized this thought experiment and gone a step further by re-creating the transistor as well. You can read detailed descriptions of these adventures in technology in his book Instruments of Amplification.
Instruments of Amplification, written and illustrated by H. P. Friedrichs, is jam-packed with nearly 300 pages of history, science background, basic theory, and hard-to-find hands-on details pertaining to the construction of an amazing array of homebrew amplifying devices.
Rooted in the same "build-it-from-scratch" philosophy that made his first book, The Voice of the Crystal, a success, Instruments of Amplification reduces complex devices to their essential elements and then shows how they can be constructed from commonly available materials.
Instruments of Amplification is available from my favourite bookseller, Lindsay Books.