This was the show that actually got me interested in reading and watching mysteries as a youth.
Of course, the original Perry Mason was before my time----I was but a wee toddler when it ended its run---but the syndicated reruns that aired after school during the early 70's piqued my curiosity about police work and what motivated people to commit crimes, though more often than not, these were murder cases.
The success of the reruns prompted CBS to revive the series in the middle 70's, but the cast was given an understandably complete overhaul. For one thing, Raymond Burr had moved on to another iconic character---Ironside, and CBS blundered, if memory serves, by putting the Fox-produced New Perry Mason, with Monte Markham (ex-The Second Hundred Years) as Mason, opposite Ironside. Talk about a suicide mission!
In the 80's, Burr returned to the role of Mason in a series of TV movies which Viacom produced for NBC. Burr passed away a few years later, and no one has attempted to revive Mason since.
The formula in the classic series became cliched rather quickly. Mason takes a case, detective Paul Drake (William Hopper) locates the clues, and, in the courtroom, Mason matched wits with DA Hamilton Burger (William Talman), winning all but one case. As a child, reruns were appointment television around 5 (ET) in the afternoon, right around dinner time.
These days, the rights are split between Me-TV, which airs Mason Monday-Friday, twice a day, and Hallmark Movie Channel, which gets a lifetime supply of weasel ears for using still footage of the open and a compacted theme in order to save time for commercials. You just don't do that sort of thing, especially to a classic piece of TV theme music like Fred Steiner's "Park Avenue Beat", which has been covered by, of all acts, the Blues Brothers!
CBS has its own YouTube channel, from whence we get this short season 1 open.