One of the few Zappa albums I own and bought this when it came out as it had the good Captain on it

Beefheart sings vocals on 'Willie The Pimp' and it was a top ten hit in the UK album charts, Frank;s first. . . . . . . . . . 

On this day in music history: October 10, 1969 - “Hot Rats”, the second solo album by Frank Zappa is released. Produced by Frank Zappa, it is recorded at T.T.G. Studios, Sunset Sound Studios in Hollywood, CA and Whitney Studios in Glendale, CA from July 18 - August 30, 1969. His first album since disbanding The Mothers Of Invention, it consists of largely instrumental jazz influenced material and feature guest musicians Shuggie Otis, Max Bennett, Don “Sugarcane” Harris, Jean-Luc Ponty and Captain Beefheart. Technologically more advanced than his previous works, it is Zappa’s first to be recorded on a 16-track multi-track recorder, which he utilizes the expanded technology to the fullest, overdubbing numerous keyboard and horn parts (played by musician Ian Underwood) as well as using techniques like varispeed to change the texture and sound of instruments. Dedicated to his new born son Dweezil, “Hot Rats” goes on to be one of Zappa’s most popular and acclaimed recordings. The albums enigmatic infrared cover photo taken by Andee Nathanson, features Miss Christine Ann Frka of the acapella girl group The GTO’s, peeping out of an empty lily pond on the estate of actor Errol Flynn. The artwork and photo collage on the inside gatefold of the LP is designed by Cal Schenkel, also responsible for the cover art on Zappa’s “Cruisin’ With Ruben And The Jets” and “Uncle Meat” albums.  When the album is reissued on CD in 1987, Zappa extensively remixes and edits the tracks, making them longer than the first LP issue. Eventually, the original 1969 mixes are reissued on vinyl in 2009 and on CD in 2012. “Hot Rats” peaks at number one hundred seventy three on the Billboard Top 200.