Publisher: Collins

First Printed: post-1974

Featured stories:
#25 - Hunting For Hidden Gold
#26 - The Mystery of Cabin Island

Cover Artist: Peter Archer

ISBN: None

Notes:
-- Has a 1973 copyright date, but the presence of The Ghost At Skeleton Rock in the list of titles on the back cover indicates a post-1974 publication date is more likely.
-- The spine of this edition features a cropped version of the cover artwork featured on the Collins edition of The Wailing Siren Mystery.

Publisher: Mulberry / Dragon Books

First Printed: 1991 (Mulberry) 1994 (Dragon)

Featured stories:
#17 - The Shore Road Mystery
#18 - The Great Airport Mystery
#19 - The Sign of the Crooked Arrow

Cover Artist: Brian Kotzky

ISBN: 0-00-694228-8 (Dragon)

Notes:
-- Two virtually identical versions of this hardback edition exist: the first credited to Mulberry (copyright page), the other credited to Dragon (copyright page).
-- The Mulberry copyright page gives the publication date as 1991, while the Amazon listing for the Dragon reprint states that it was issued in 1994.

Publisher: Dragon Books

First Printed: 1991

Featured stories:
#20 - The Clue In The Embers
#21 - What Happened At Midnight
#22 - The Sinister Signpost

Cover Artist: Brian Kotzky

ISBN: 0-00-694235-0

Publisher: Mulberry / Paragon

First Printed: 1992 (Mulberry) 1995 (Paragon)

Featured stories:
#47 - The Jungle Pyramid
#48 - The Firebird Rocket

Cover Artist: Unknown

ISBN: 0-752-50942-X

Notes:
-- This omnibus was later reprinted by Paragon Books in 1995 and 1996 with the same cover design.

Publisher: Mulberry / Paragon

First Printed: 1992 (Mulberry) 1995 (Paragon)

Featured stories:
#49 - A Figure In Hiding
#50 - The Secret Warning

Cover Artist: Unknown

ISBN: 0-752-50947-0

Notes:
-- This omnibus was later reprinted by Paragon Books in 1995 and 1996 with the same cover design.