Children of the Future (1968) is divided into two "halves" including: (1) the (nearly) 18-minute "Children of the Future" suite; and (2) six songs.
The Children of the Future suite is presented as a five-part song cycle/multi-movement suite hybrid (with the opening theme restated at the end) and is a superb example of proto-progressive rock. Although I enjoyed the entire piece (including the first five minutes of psychedelic pop), as a huge prog rock fan I was especially delighted with the spacey Hammond organ and mellotron playing on the haunting, achingly beautiful, and classically-influenced fourth part, "In my First Mind" (7'38") (as a side note, the fourth part was co-written by Steve Miller and keyboardist Jim Peterman, who obviously contributed the proto-prog aspects). The mellotron with the string setting is featured prominently throughout "In my First Mind" (to an even greater extent than the Moody Blues), and anticipates similar use of the instrument by British proggers King Crimson on their 1969 debut. This is but one example (of maybe five or less) where an American band actually used the mellotron. The fifth and final part of the piece, "The Beauty of Time is that it's Snowing" displays use of the avant-garde "found sound" technique that other experimental bands were exploring at the time. For example, atop a soft organ drone there is the sound of calling gulls, a subway, a conversation, a human voice shouting, a door sliding shut, a "radio" playing blues music, and the howling wind. In summation, Parts 4 and 5 collectively span 13 minutes and are simply excellent.
The second "half" of the CD is situated 180 degrees away from the experimental material of Children of the Future and features six, simpler songs. The songs range from the pastoral, psychedelic, and slightly jazzy blues of Boz Scaggs "Baby's Calling me Home" (which features just a harpsichord and acoustic guitar), to the heavy, "Cream-like" blues rock of "Stepping Stone", to the traditional (straight) blues pieces "Fanny Mae" and "Key to the Highway", which feature the harmonica as a solo instrument.
This recording is a great example of how late 1960's proto-progressive rock bands mixed disparate styles into what was (at the time) heralded as the new music that would "change the world". Ultimately this "third stream" style morphed into the prog rock of the 1970's. Chances are that if you liked this recording, you may also like two recordings by the English proto-prog band Procul Harum: "Shine on Brightly" (1968), which also features a lengthy multi-movement suite, and "A Salty Dog" (1969), which has a similar mixture of blues and psychedelic pieces.