We aren’t sure that a PDF with 100 pages in it qualifies as a pocket reference, but TI’s Analog Engineer’s Pocket Reference is certainly a good read. You do have to register with TI (use a disposable address if you are too paranoid to do that), but the free download is well worth the effort. The document’s been around for awhile, but TI recently released a new 4th edition.
The first few pages might underwhelm you. You probably know the standard decimal prefixes and are more likely to ask Google to convert circular mils to square millimeters, for example. The second part, though, gets more into electronics. There’s standard values for resistors and quick reminders about the difference between X7R and Y5V ceramic in capacitors, for example.
Things get progressively more interesting, covering measurements and phase shifts, and then amplifiers. The little circuits are pithy but cover the bases including things like frequency response.
You have to build that amplifier on something, so the next section covers PCBs and wires. If you can’t remember how far apart traces need to be to handle 50V, the pocket guide will remind you. The section includes references to standard packages and loads of other data about PCBs and wire (including coax).
The last few chapters cover sensors and A/D conversion. We guess these days even an analog pocket reference has to have some digital thrown in. Even if you mostly do digital designs, a lot of the information about basic components is still relevant.
The book is concise, detailed, and free. What more do you want? If you crave a hard copy, they do sell printed versions. We found ourselves wishing the online version was a Wiki instead of a PDF, but then again that would be harder to publish as a book, and we like that, too.