The BHP originates from 1935. It was John Browning's last design, developed further by an FN wizard before its release after his death. Its features have been much copied, as it takes much from Browning's 1911. It's 9mm, and it is in many ways refined from the 1911.
A BHP was my second medium-caliber shooting pistol; I bought it new from a local dealer. I had been shopping for something that would be accurate and take a load off my only other 9-at-that-time, a Walther P99. Something that would feel good and shoot well for me. I handled a lot of different makes, and was lucky to be able to shoot some of them. Although I never got to test a High Power, they're -- iconic. And absolutely beautiful in blue, particularly in high-polish blue. There are models with quality adjustable sights, and there are some aftermarket accessories available. FN built them for Browning until a couple decades ago. I believe that all current Browning High Powers' parts are still made in the same FN armory in Belgium, but like mine, are assembled in Portugal. The Portugese do a fine job of it.
The BHP, in my hand, feels great: it just points. It's neither huge nor petite; it's a 13-round double-stack, a slimmish full-size gun. For me, the balance is fab, and out of the box, it is an excellent shooter. Mine is very accurate, with a fine lockup and tight slide fit. It shot flawlessly from the start. At four years and 6-8K rounds of commercial ball, it's not had a single hiccough apart from my 2 rounds from a single box of WWB that wouldn't chamber in the BHP or three other guns, and my own early reloads.
Fine balance and feel, tough, elegant aesthetic design, accurate and reputedly durable. It's been in continuous production and refinement since its release over 60 years ago. There's a Wikipedia article that will tell of its history. It's been made in other factories around the world, and has been much copied in others. The Browning original is the best.
I've fired CZ 75 and 85 at the range, and dry fired the newer P series. They, too are excellent guns, and in today's world a very popular police and military sidearm. CZ has been refining this design for over thirty years. They're finely made, tight, very accurate, and may have a slightly better trigger than the High Power. But the HP's is still very fine: crisp with an indiscernible break, moderate travel, and smooth, despite a little friction from the (yeah) magazine safety. Fairly, the CZs have moved into the market that the HP dominated until the 1980s.
My own now has a JP red dot sight, nice grippy Hogues, and a Barsto match barrel, and it's been a joy, a favorite. Any person looking for a 9mm with a more modern ergonomics than a 1911 but still retains the feel elegance, should hold one of these.
There are quite a few sources for barrels, triggers, sears, springs, grips, and even some for sights and optical sight adapters. (My optical sight uses a slim adapter that fits the slot where the stock fixed sight was.) Standard magazine in most states is 10-shots, but 13-shots were the original and still most widely used. Meg-Gar and perhaps others make a 15-round magazine, and there are 20- and 32-round mags out there. I don't think I'd like that balance so well, though.
It is also available in .40, a recent development. The .40 has a redesigned heavier frame to support it.