Condi's recommends are very good.
If you want to dig deeper into European Medieval Armour in particular - for a cheap, fast overview with lots (130) of illustrations in c100 pages get yourself a copy of Arms and Armour by Vesey Norman - 1964 but reprinted several times - c£6 in paperback or slightly more in hardback. Covers Norman mail hauberks through to the early C17th. Also covers very basic intro to swords and daggers.
If you want the key groundwork book - poorly illustrated but it goes through the whole of medieval european armour find a copy of European Armour by Claude Blair 1958. (Don't get confused with Studies in European Armour by Blair et al - that is a study of the Kienbusch collection 1972 (worth a look but not what we are talking about). Blair's book comes up on the usual second hand markets from c£50 to £150 depending on the quality (lower end ex library books - with stamps, fly leaves missing,etc - but the text is usually okay, to clean first run copies at (and above the upper price range). If you want a copy for the text and aren't a collector the £50 copies are perfectly okay.
There are hundreds of others which all cover much the same ground as each other, aren't as good as Blair, but have much better illustrations.
You can go to a few hundred pounds for books like Masterpieces of European Arms and Armour in the Wallace Collection Introduction by Capwell and Edge (Text is based on James Mann's 1962 catalogue and AVB Norman (Vesey)'s Wallace catalogues. It comes as a box set with a flash drive of the full 7,000+ photograph catalogue of the collection, hence the £175 price tag. There are still a few new copies available - not from the Wallace collection itself but on Amazon and a few other outlets - buy now as second hand copies are double the price at least - and make sure you get the full box set with USB if you go for it!).
On the other hand you can stick with Vesey's £6 version!
On jousts/tournaments - again Condi's recommendation is good - if you want to go to an original available source -you can get a copy of the History of William Marshall (L'Histoire de Guillaume le Marechal) a thirteenth century epic verse biography of the Mohammed Ali of the Tournament circuit. There is a lot in there about his tournees - large scale fights - you needed a team to play - and the basic purpose of the circuit - money and fame. Hard going but it is available in a modern English translation from Boydell and Brewer c£18 paperback.