The cover image is a composite of two interior panels:
The story contents are as follows:
Escape from the Planet of the Apes [Part 4]: In The Cradle Of A Father's Sins, originally published in Planet of the Apes #15, December 1975
Escape from the Planet of the Apes [Part 5]: When The Calliope Cries Death, originally published in Planet of the Apes #16, January 1976
Escape from the Planet of the Apes Part 6: But Who Shall Inherit The Meek?, originally published in Planet of the Apes #16, January 1976
Conquest of the Planet of the Apes Part 1: Slaves, originally published in Planet of the Apes #17, February 1976
The centre of the book contains the following two non-comics feature articles:
Man The Fugitive, originally published in Planet of the Apes #7, April 1975
Interview With Dan Striepeke, originally published in Planet of the Apes #5, February 1975
The GCD and other sites reference But Who Shall Inherit the Meek? as And Who Shall Inherit the Meek? Planet of the Apes #16 refers to the story as "And..." on its index/title page, even though it is "But..." (or, strictly speaking, "but" in lower case) on the story page. There is no such title page in the Newton printing, so But it is.
Slaves is a 21 page story - only 16 pages are reprinted in this issue.
Man the Fugitive is a 7 page feature in Planet of the Apes #7 but it is only 6 pages in the Newton edition - the first page has been dropped, seemingly for the Deadly Hands of Kung Fu in-house advertisement which precedes this feature.
Planet of the Apes #17 advised that the next issue would contain In The Cradle Of A Father's Sin. On the basis of the inclusion of this story in this issue, it stands to reason that this unnumbered issue would be the 18th issue in the series.
However, as counterintuitive as it is, it is now evident that this issue was actually preceded by Planet of the Apes #NN, which compiled the previously published instalments of Kingdom on an Island of the Apes. This post originally had the issue number designated #NN but given the new information to hand concerning the post-August 1976 period I have amended the post to reflect the issue number as #NN.