
There is a new guidebook to Colchester Castle by Tom Hodgson and Philip Wise (Jarrold Publishing and Colchester Castle, 2015). This beautifully designed and colour illustrated book of 72 pp follows the history of Colchester through the collections displayed in the Colchester Museum.
The castle itself is built on the foundations of the Temple of the Divine Claudius destroyed during the Boudican revolt.
The main sections are:
a. Iron Age (including the Sheepen Cauldron dating to 1275-1140 BC; the Mount Bures Firedog; the Augustus Medallion from the Lexden Tumulus)
b. Roman Invasion (including tombstones of veterans from the colony; the Fenwick Treasure perhaps deposited during the Boudican destruction)
c. Roman Heyday (including slave rings; ‘the Colchester Vase’ showing gladiatorial combat, dating to AD 175-200; lead curse tablets; the Colchester Sphinx excavated on the site of the Essex County Hospital in 1821)
d. Roman Decline (including Christianity in Roman Colchester; jet bear)
e. Saxons and Normans (including St Botolph’s Priory; the Town Charter)
f. Medieval (including Medieval painting)
g. Post Medieval (including the Colchester Martyrs; the Siege of Colchester in the Civil War)
h. Modern (including the formation of the museum collection; Colchester Castle in wartime including an exhibition in 1944)
Inside the back cover is a plan of Colchester pointing visitors to key locations around the town.

I have two other guides to the collection: Colchester Castle: a history, description and guide (Colchester Borough council, 4th edition, 1978). This includes plans of the castle and a more detailed history. There is also a section drawing showing how the castle included the Roman temple in its foundations.

The second guide is Roman Colchester by M.R. Hull (Colchester Town Council, 1947). This was prepared ‘in response to a great demand among visitors to Colchester Museum for a Guide to Roman Colchester’. The sections are:
1. Colchester before the Romans
2. The beginnings of Roman Colchester
3. The colonia
4. Boadicea
5. The visible remains of the Roman town
6. Civic organisation and administration
7. The Middle Empire
8. The legend of King Coel
9. The end of Roman Colchester
There is a particularly useful foldout paper plan inside the back cover.
One of the earliest guides is Dr J. Horace Round’s The History and Antiquities of Colchester Castle (1882).