There are two background sections the reader can work through before jumping into quantum computing. These sections are not rigorous and do not act as a replacement for a decent grounding in matrix algebra, vector spaces and basic computer science principles. For readers that are lacking in one or more of these areas, there are recommended texts below.
The purpose of the preliminary mathematics section is to refresh the reader on important definitions, and to act as a check-list to make sure the reader is comfortable with the necessary maths. If any of this maths (with the exception of Dirac notation) is new to you, I would recommend you read a more rigorous introduction to maths for quantum mechanics.
The computer science section contains a summary of important concepts, but unlike the maths a deep understanding is not essential. It is important however that the reader is familiar with the terminology and ideas, and if they are not then I recommend reading around the topic before continuing.