Before filing a complaint:
- plaintiff (P) contacts law firm, inquires about infringement case. Discuss fees & other matters to determine if client actually wants to continue.
- identify patents at issue, accused products/services, perform prior art searches, possibly obtain opinion letters on patent validity, sketch out damages to again re-assess whether it's worth going forward.
- engage in saber rattling by calling/emailing/writing defendant, see if settlement is possible.

P: File complaint / serve process / amendments by right

Defendant (D): Pre-answer motions
- allege court has no jurisdiction, P has not stated a claim, etc.
- typically leads to further amendments of the complaint by leave of the court.

D: Answer, affirmative defenses, counterclaims
- affirmative defenses include "your patents are not valid for the following zillion reasons," which is why they were vetted before the start of litigation: in anticipation of these defenses.

P & D: begin discovery
- zillions of requests for admission, demands for document production, interrogatories
- especially popular are "30(b)(6)" depositions, where you depose "a corporation", essentially requiring them to send an agent who can answer your questions, or tell you who can.
- the results of discovery are the raw material for trial-admissible evidence.

P & D: obtain expert witnesses
- Will typically address questions such as the state of the art in a certain industry at a certain time, the ordinary skill of a practitioner in a given industry, etc - mostly for patent validity issues.

P & D: pre-trial hearings
- Regular scheduling conference, like all federal litigation
- Unique to patent litigation, Markman claim construction hearing. As per an appeals court decision, deciding the meaning of patent claims ("claim construction") is a matter of law for the court, and not for the jury. Therefore the judge sets a Markman hearing before trial during which he will decide the meaning of the patent claims.

A cynical perspective on Markman hearings is that the judge looks at each party's asserted claim sets, picks one, and says "this is what the patent means." Some judges are more sophisticated in their analysis, but the Federal Circuit has a VERY high reverse rate on claim construction, so some courts seem to think "why bother, I'm likely to be reversed anyway."

It is difficult to overstate the importance of the Markman hearing. Depending on exactly what the judge holds the patent means, the issue of infringement frequently becomes either a shoe-in or a complete hail mary. Parties frequently settle or successfully move for summary judgment after the Markman hearing, thus avoiding trial completely.

Typically this will be followed by an appeal to the federal circuit, which will do the REAL claim construction and then it's pretty much over (The supreme court rarely takes patent cases). But:

P&D: Trial
- if any factual issues remain in dispute after discovery and Markman, the parties can move on to a trial.
- In the patent validity area, certain issues related to the obviousness of a given invention may be resolved by a jury. Typically, accused infringers hate for it to reach this stage, since it's easy to make inventors appear brilliant and their inventions non-obvious.
- In the infringement area, the ultimate issue of infringement is up to the jury.

P/D: Appeal
- If either party doesn't like the outcome of the trial, they may appeal to the Court of Appeals for the Federal Circuit, which by federal statute has exclusive jurisdiction to hear appeals of patent cases. See above.

Oh yeah, not to mention Patent reexamination proceedings, which are quasi-litigation affairs before the USPTO wherein one party tries to invalidate another's patent. Typically occur before litigation, but sometimes as a last-ditch effort during litigation by an accused infringer, since under some circumstances the decision of the PTO is considered binding on the court (the district court at least; reexams can be appealed as well). See, e.g. the Blackberry patent fiasco, where RIM finally tried to get the Blackberry patent reexamined late in the litigation game.