the conspiracy of catiline as seen by contemporaries and historians, updated

 (by no means complete)

The contemporaries:

The Catiline Orations, with text links (Cicero, of course)

Sallust: Conspiracy of Catiline  (e-text)
The Jugurthine War & The Conspiracy of Catiline (print)

The ancient historians/biographers:

Update 1

Appian
Bellum Civile II, 2 ff

Suetonius, De Vita Caesarum, Divus Iulius, Chapter XIV.

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Casssius Dio, Roman History
Book 37, Chapter 29 ff

Florus, Epitome de Tito Livio II.xii

Plutarch

Life of Cicero, Chapter 10 ff
Life of Cato Minor, Chapter 22 ff
Life of Caesar, Chapter 7 ff
Life of Crassus, Chapter 13

The modern historians:

History of Rome: The Establishment of the Military Monarchy
by Theodor Mommsen  p. 62 ff (e-text)
Sallust (Sather Classical Lectures)
by Sir Ronald Syme
From the Gracchi to Nero:  A History of Rome from 133 B.C. to A.D. 68
by H.H. Scullard  p. 105 ff
The Last Generation of the Roman Republic
by Erich Gruen  interspersed through the book which is organized by themes
Cicero: The Life and Times of Rome's Greatest Politician
by Anthony Everitt
Cicero
by D.R. Shackleton Bailey

        

More later on JSTOR articles.