Piano Tuning: A Simple and Accurate Method for Amateurs (Dover Books On Music: Piano) / J. Cree Fischer,

If you have a note that has dropped in pitch, do you have to call in the tuner? A stuck key? Sympathetic rattle? Missing bridles? A broken hammer shank? An unglued ivory? The answer, in each case, is no: you can make all of these repairs yourself!
This is the clearest and most complete book available for beginning tuners and amateur pianists. It explains all the basic processes practically and with model clarity. A non-musician can use this book without too much difficulty.
You will learn how upright, grand, and square actions work, and how to take care of the smallest repairs — repairing stuck keys, poorly adjusted bottoms and capstans, crowded back checks, felts and leather on the hammers, hammer stems; softening damper and hammer felts; installing new bridles; eliminating "sympathetic rattle"; all with a minimum of tools and training.
You will learn a professional method of tuning based on slightly flattened fifths, where only the octave and the upward fifth intervals are used. This is one of the easiest systems to learn, one capable of a great deal of control, and one perfectly suited to adjusting one or two keys. It is a tested method especially right for amateurs working without a teacher, and a method that trains the ear for other recommended systems. The author also explains "beats," the theory of the tempered scale, and useful experiments you can make with harmonic phenomena.
If you want to experiment with tuning a piano, there is no better book to start with. It will help performers and teachers make occasional repairs and learn the structure and scale of the piano. Those who want to know how pianos work will find this book both clear and useful.