The data sheet is here. Manufactured by National Semiconductor, this 16 pin DIP TTL chip has 4 positive-edge triggered D flip-flops, with true and complemented (inverted) outputs. All 4 have a common clock connection to save pins, and all 4 have a common 'reset' pin, which when held low, sets all the stored values in the D flip-flops to 0 (low). It is a member of the "fast" TTL family. Rather than "LS" or "ALS". It is as you would expect - this means it is fast. The data sheet says it is guaranteed to be fast enough to switch states with a clock frequency of 100 MHz, but what is typical is 140 MHz.
For sheer utility for screwing around with digital electronics, this is probably the best chip to buy, even more than nand gates, I'd say. The need for these simply comes up more often than logic gates, and you quite plainly can do more neat things with them using fewer chips than anything else, I'd say, but it of course depends on what you have in mind to do.