Time & Chaos/!ntellect
Time & Chaos (T&C) is a 'Personal Information Manager' with has three main sections that handle contacts, appointments and tasks. It was first released in 1991 as a shareware with a buy price of $19.99. It was and still is written by Michael Whittington who originally formed a company under the name of 'Isbister' changing to 'Chaos Software' in 200x. In 200x !ntellect (!) was released, with all the features of T&C with the addition of a combined email client.
Chaos Software's website can be found here.
A major feature of T&C is its 'All-In-One' screen layout.