I've been lucky to find two decent used bookstores within driving range from here, and made some really decent scores at them from time to time. I find that for the basics, physics books (not necessarily textbooks) from the WWII era till maybe the 60's are a good find. It seems that back when the discoveries were new, there was more emphasis on sharing them in language you can understand, with details more often than not completely so left out of more modern literature I'm beginning to think the authors of the new stuff simply do not know themselves. The constant flow on the science blogs on the 'net of "new discoveries" that are documented in 50-60 year old books tends to reinforce that belief. It seems very few modern professional scientists actually know very much and a PhD is now just a testament to patience, not knowledge or the ability to do real things that mean much. Not to insult academia too much, there are of course exceptions to that -- those that really love their field tend to go out on their own and really learn it a lot better than they did while in school, and in fact, when I hire people that is one of the first things I ask them -- what do they do when not at work? Do they have a lab? Do they do cool things in it? If I get a blank stare, that's it for that candidate -- and the practice has paid off quite well in the businesses I've run.
Here's some books to look for:
Electrical Engineer's Handbook, by Fredrick Terman -- about the best there is, all the basics from zero up, little on semiconductors as it was printed at the end of WWII. The concepts are all still correct, and he has electron optics that no other source really has. A steal at any price.
On that same idea, here's a freebie for you, the RCA electron tube design book. They wrote this inhouse to bring the new guys up to speed on the technology they used. Some of it is useful for fusor builders too. After all, with scaling for charge/mass, one charged particle is a lot like another and tube were worked out quite thoroughly. I've often wondered why this kind of thing hasn't been more mined by physicists, especially amateur ones.
It's like tossing nearly 100 years of good work in the trash. That's just ignorant. Here is the classic paper on beam power tube design -- it covers space charge effects that can work for or against you which is a very serious effect in fusors -- more there than in any electron tube due to slower flight times of ions.
Old ARRL handbooks. There is a sweet spot from the times when most amateur radio operators built their own gear, and usually the basic electronics sections in the older ones is about the best beginner's tutorial out there anywhere. Collect a few from different periods so as to span the range of what can be done fairly easy by a true home experimenter, and again, the same concepts that apply there will help you out on things like signal generation and instrumentation. Here is one to get you started, not the best, but again, found online and presumably not in copyright. As with other book links here -- it's too big to get on a slow connection.
Fast Neutron Physics (two volumes, often expensive even used), and Progress in Fast Neutron physics. Hardly ever found cheap, but again, worth it for anyone doing fusors for the instrumentation and tables alone. These are selected papers by people who actually do this stuff, not the usual BS that is trying to impress some thesis advisor with bafflegab.
ISBN (original two volume set) Oops, doesn't exist -- these are Rice university publications.
Rev Sci Ins -- sometimes someone dies with a nice library, and of all the normally high priced journals, this one is closest to worth it, though if you're lucky you may need a truck to haul away a collection. Rent one if you need to and throw something else away to make space for it. Last I checked, a subscription with access to back issues for this taxpayer funded research cost an amateur about 60 grand -- yes, that's with the discounts for small outfits, but in a bundle that would make most cable TV outfits green with envy. The only other way to get this stuff is to know some college students who can download it from their libraries and steal you a copy of this or that, piecemeal. But they often won't follow their noses the way you might follow yours...which results in getting some "interesting papers" and can be good in its own way.
Anything by Walter H Kohl on vacuum tubes, materials. The newest one is titled Handbook of Materials and Techniques for Vacuum devices, which we bought new at a very high price, and it was worth it anyway, but he wrote a total of three versions, and they are all good. Probably the most important book you can own if you make fusors and want to know how the experts in vacuum devices really did things, full of practical hands-on details on just about every topic related to that. Rarely, you'll find a scanned version out there on the web of one of the older more specialized versions, and it's worth the download, maybe even the wear and tear on a printer. Again, this guy was there and did that, and tells all about that stuff you'd miss, unexpected consequences, what really works every time, all the good stuff. Here is a link to an older version of his stuff that I think is not copyright -- warning, its a lotta megabytes. I also mention this in materials with info on how to buy the new version. It's really worth it.
John Strong's Procedures in Experimental Physics -- a classic, and what was hard then is easy now, but this gets to the nitty gritty of how it's done and really isn't obsolete at all. I learned a lot by simply going through it and duplicating his results on the things I found interesting. You can get this one from Lindsay publications, the lost technology series, new. It's not expensive, and that outfit deserves to get money for what they are doing so we don't lose the cool older stuff.
Instrumentation in High Energy Physics edited by Fabio Sauli -- bought new here (at extreme price) but there ought to be some used out there too. Higher energy than fusor types, but again, a good survey with concepts on detector designs of all kinds -- you just have to read it knowing that a lot of it cuts off at energies higher than the max a fusor operator will be seeing. ISBN: 981-02-1473-1
If you ever wanted to really understand the math behind that little symbol physicists toss around when talking about wave equations (which I suspect most don't understand themselves), get
Practical Quantum Mechanics, by S. Flugge -- that little symbol means about 20 pages of dense equations I don't think are free of flaws....nuff said, but it's nice to know the dirty undersides of things sometimes. Got this in the used store. ISBN: 3-540-07050-8, or 0-387-07050-8 Why there are two on this book I don't have a clue.
Building Scientific Apparatus by Moore, Davis, Coplan is a good intro to a lot of topics, despite the execreble section on electronics -- that part is often wrong and out of date at the time of publishing, but the other half is good. Kind of the next step after the John Strong book. ISBN 0-8133-4006-3
Here's a link to some documents I've found useful, mainly about gas tubes and their uses. A fusor has a lot in common... Chapter 8 of the Phillips book describes a borehole neutron generator in enough detail to make one -- with impressive specs, as well as a gas triode I laughed about when about 6 months ago it was "invented" at MIT by someone evidently ignorant of history. As seems to be the case with most outfits -- science has become far too specialized, resulting in a lot of duplicated effort, and no one bothers with the old stuff (to their peril). MIT probably even patented their version....and our patent office is broken by design re prior art (depends on the submitter to find it, which they have zero incentive to do), so it probably went through.
Last for now, but probably very far from least, Introductory Nuclear Physics by DAvid Halliday for an Asian publishing division of WileyTuttle is a must have indeed. Not only does he give both the simple math and in real units you can use, but real examples you can check your math against. This guy worked in an earlier time (before quarks etc) but his predictions were prescient indeed -- impressive. I like this sort of thing where "we did this, and then we saw that" without the crap you so often see in modern work, which tends to say "we did an experiment, but the details would bore you, and saw some data, which we are not revealing in raw form, because it's to noisy to mean anything, and we say it means this -- with little or no justification or even math that you can use to make useful predictions.
This is the other extreme -- good stuff.
More later -- you all chime in now and give us your goodies on this topic. We have to stand on some giant shoulders to be good at what we do -- which ones do you stand on?