AllMusic (previously known as All Music Guide or AMG) is an online music guide. The largest music database on the web, it catalogs more than 3 million album entries and 30 million tracks. It was launched in 1991, predating the World Wide Web. 
AllMusic was launched as All Music Guide by Michael Erlewine, a "compulsive archivist, noted astrologer, Buddhist scholar and musician." He became interested in using computers for his astrological work in the mid-70s, and founded a software company, Matrix, in 1977. In the early '90s, as CDs replaced vinyl as the prevalent format for recorded music, Erlewine purchased what he thought was a CD of early recordings by Little Richard CD. After buying it he discovered it was a "flaccid latter day rehash."  Frustrated with the labeling, he researched using meta data to create a music guide.  In 1990, in Big Rapids, Michigan, he founded All Music Guide with a goal to create an open access database that included every recording "since Enrico Caruso gave the industry its first big boost".
The first All Music Guide was a 1,200-page reference book, packaged with a CD-ROM, titled All Music Guide: The Best CDs, Albums & Tapes: The Expert's Guide to the Best Releases from Thousands of Artists in All Types of Music.Its first digital iteration, in 1991, was a text-based Gopher site. It moved to the internet as web browsers became more user-friendly. 
Erlewine hired a database engineer, Vladimir Bogdanov, to design the All Music Guide framework, and recruited his nephew, writer Stephen Thomas Erlewine, to develop editorial content. In 1993, Chris Woodstra joined the staff as an engineer. A "record geek" who had written for alternative weeklies and fanzines, his main qualification was an "encyclopedic knowledge of music". 1400 subgenres of music were created, a feature which became central to the site's utility. In a 2016 article in Tedium, Ernie Smith wrote: "AllMusic may have been one of most ambitious sites of the early-internet era—and it’s one that is fundamental to our understanding of pop culture. Because, the thing is, it doesn’t just track reviews or albums. It tracks styles, genres, and subgenres, along with the tone of the music and the platforms on which the music is sold. It then connects that data together, in a way that can intelligently tell you about an entire type of music, whether a massive genre like classical, or a tiny one like sadcore."
In 1996, seeking to further develop its web-based businesses, Alliance Entertainment Corp. bought All Music from Erlewine for a reported $3.5 million. He left the company after its sale. Alliance filed for bankruptcy in 1999, and its assets were acquired by Ron Burkle's Yucaipa Equity Fund. 
In 1999, All Music relocated from Big Rapids to Ann Arbor, where the staff quickly expanded from 12 to 100 people. By February of that year, 350,000 albums and 2 million tracks had been cataloged. All Music had published biographies of 30,000 artists, 120,000 record reviews and 300 essays written by "a hybrid of historians, critics and passionate collectors". 
The All Media Network also produced the AllMusic guide series, which includes the AllMusic Guide to Rock, the All Music Guide to Jazz and the All Music Guide to the Blues. Vladimir Bogdanov is the president of the series.
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