Doo-Wop is a genre of rhythm and blues music that originated in African-American communities during the 1940s, mainly in the large cities of the United States, such as Pittsburgh. It features vocal group harmony that carries a melodic line to a simple beat with little or no instrumentation (Classical Doo-Wop though tends to have more instrumentals). Lyrics are usually about love, sung by a lead vocal over background vocals, and often featuring, in the bridge, a heartfelt message addressed to the beloved. "Classical" to "Post Doo-Wop" is what you will tend to find in Chad's playlist. These songs span typically from 1955 to 1964 & present day Doo-Wop. 

Classical Doo-Wop is a phase featured of tight and sweet harmonies; however, the lead singers lost much of the smoothness when switching from paleo-doo-wop recordings (which is the era of doo wop prior to the classical stage). During the classical era of Doo-Wop, Bass singers were given a more prominent role; in the past they had tended to function just as part of the background harmony. The performers were generally quite young, featuring lyrics primarily concerned with young, idealistic love. Instrumentation remained in the background, albeit with a heavy backbeat. The classical period saw the development of a wide array of spinoff styles, in part a response to newly devised marketing strategies. Styles like "Schoolboy doo-wop." Where a male ,usually in his early teenage years, would take on singing. While Frankie Lymon was the definitive interpreter from the standpoint of both commercial success and singing prowess, he has many imitators, such as Little Anthony. "Gang doo-wop" broke off of classical, where the lead singers studiously avoided being smooth; rather, they seemed to swagger as they sang. Major groups and singers included The Channels and The Collegians. From those also came "Italo-doo-wop." This variant was distinguished by even tighter group harmonies, roughly-hewn tenors pushing their upper registers to produce a "sweet" sound, and the prominence of bass singers (the latter a premonition of the neo-doo-wop phase). Notable groups included The Capris, The Classics, and The Elegants. Finally the branch "Pop doo-wop," which was heavily influenced by the commercial mainstream going as far back as turn-of-the-century barbershop quartets, this style had little in common with classic doo-wop other than tight harmony. Practitioners developed a number of ploys geared to making inroads into the pop market, most notably (1) cover records, (2) softening the doo-wop sound in order that it might reach a broader range of age groups, and (3) jazzing up adult-oriented standards so as to appeal to youth. Among the more popular groups in this era were The Duprees, The Fleetwoods, The Temptations, and The Tymes.

Neo-Doo-Wop is the era of Doo-Wop which was considered the oldies revival (largely focused on doo-wop) which began in 1959. Although neo-doo-wop maintained the simple melody lines and preoccupation with love lyrics typifying the classical phase, the distinctive features of doo-wop were greatly exaggerated; this style had a greater preponderance of falsetto leads, heavier and more pronounced bass singing. Instruments also figured more prominently in song arrangements. Notable singers and groups from this era included Gene Chandler, Dion with the Del Satins, and The Reflections. The absorption of new talent from a variety of backgrounds spurred the development of new stylistic subcategories. "Tin Pan Alley Doo-Wop." Exposed to doo-wop as well as schooled in music composition, young songwriters created their own formula. They melded doo-wop conventions with more complex melodies, augmented instrumentation, and thoroughgoing production values. Key artists and groups included The Chiffons, Randy and the Rainbows and The Tokens. "Distaff Doo-Wop." With few exceptions, women didn't play a prominent role in doo-wop until the Tin Pan Alley variant achieved popularity.  "Garage Band Doo-Wop." Denotes material recorded on substandard equipment.  "Novelty Doo-Wop." Almost without exception, this genre encompasses humorous, uptempo material. Themes covered include fantasy , and media heroes. "Pseudo-Doo-Wop," which is the final category, refers to the doo-wop style minus the vocal group format. Major groups which included solo efforts Rosie and the Originals, Don and Juan, and Robert and Johnny.

Post Doo-Wop is, for or all practical purposes, the genre ceased to function in a creative sense as elements associated with it virtually disappear from recordings. With few exceptions, words replaced nonsense syllables as background responses, harmony receded into the background, falsetto appeared less frequently, the bass was used less as a separate voice, instrumentation took on much greater importance, and melodies exhibited a much greater degree of variation. A number of groups--most notably the Drifters, the Four Seasons, and Little Anthony and the Imperials--crossed over into the pop mainstream. The primary innovations in vocal group singing now took place within the a cappella genre.